Chase And Status

It’s been a while hasn’t it? And with good reason really. I’d finally gone out and bought a bike that needed absolutely nothing doing to it. Just at the time that we were all locked down again, and so I ended up with a load of time on my hands and no engines that need rebuilding, or looms that needed modifying, or bodywork that needed painting. I was a little lost actually – and ended up rekindling some old hobbies while I waited for the weather to turn, and lockdown restrictions to ease.

And so, this weekend, I finally got out on the road for a few hours to give the 675 a quick whizz to see what it was like as a roadbike. I knew full well that as a trackbike it’s a bit of a weapon, having ridden James’s 675R at Cadwell last year, and spent some time chasing down a couple of 675s on my old ZXR750. But as a roadbike, is it actually any good? Quick answer: yes. For the most part, anyway… I was pottering around yesterday when I was passed by someone on a GSX-R something, obviously in a hurry to get somewhere. And I did something I’ve not done in many years, and dropped it a couple of gears to see if I could catch up. The chase lasted about 12 seconds I guess. It’s really a very potent machine on the road – possibly slightly too fast for my liking. It certainly felt a lot quicker than the ZXR750s, and right up there with something like an early model Fireblade. Litre bikes are just not my thing I’m afraid. I’ve ridden all sorts – ZX10Rs, R1s, Ducati 1098, GSX-R1000s etc. And while they all offer stomach churning acceleration and wheelies on demand, that’s just not my bag. Braking and handling are where I get my kicks, and it’s safe to say that the 675 excels at both of these. The brakes are truly noteworthy – every bit as good as the brakes we had on the endurance 750SRAD.

So then, as a road bike, it’s very quick, quite comfy, and supremely unsuited for carrying luggage. No surprises there. It’s right at the limit for seat height that I’m comfortable with. I have a reasonably average sized inside leg, so I’m not sure if this one has been jacked up at some point, or that’s just the way they are – I need to see if I can blag a ride on another of the same vintage to check. I have my suspicions about the electrical longevity too, after it killed a battery last week for no apparent reason. I’ve read in a couple of places that this just happens from time to time, and it’s either the stator, or the reg/rec, or both – so I’m going to need to keep an eye on that I guess.

Other than the battery, it’s all been pretty dull really. I replaced the dreadful Dunlop Lurchmaster3000 tyres with some Conti Race Attacks, which are complete overkill for the road but they were such a good price I couldn’t resist. Otherwise all that’s happened is stuff to put it back to standard – levers, rear footpegs, and junking the ridiculous tail ‘tidy’ to put a stock unit back on. And it really comes to something when an oil change is one of the most interesting things to talk about, but yes, I changed the oil. This was just me being paranoid – I was reading through the old receipts that came with the bike, and noticed that the last one contained an item for three litres of oil at £7 a litre. Which sounds suspiciously cheap for a 14000rpm motor. For now, I’ve replaced it with Motul 5000 which while it isn’t the best oil in the world, it meets all the specs laid out in the workshop manual, and on the road I’m not going to be stressing things anyway. Before I head out on circuit again I’ll be dropping that and filling it with 300V.

That’s it really. It’s a very pretty thing, which is a little uncompromising, and goes like the clappers but feels a little fragile. I’m not sure there’s much else to say really. I think I’m going to like it.

A Taste Of Honey Is Worse Than None At All

Previously in TRX world I rebuilt a dead engine, then killed it on the dyno, then fitted a new engine and killed that one too. On the face of it, things weren’t looking too great really, but I’ve always liked a challenge. And the opportunity to properly re-equip my garage and build a good engine was really too good to miss. Essentially, this is exactly what happened. As we left things last time (quite some time ago now, sorry, I’ve been lazy) I’d collected two spare derelict TRX850s, and stripped the crank and shells from the best one to put into my engine. The rest of the rebuild went surprisingly smoothly. I took the opportunity to give everything a really good clean up, and replace gaskets and seals all over the place while I was in there, to hopefully give the engine the best shot at a long and happy life. I also swapped the clutch plates and steels with some of the huge collection of spares, as they measured up with a bit more life in them. 

The one thing that I did kind of bodge my way around was the charging wiring circuit. Way back in the mists of time, the connector from the alternator to the loom got a bit hot and melty, so I just hacked it out and soldered it in place, with a view to replacing the connector at some point. This bodge worked so well that I completely forgot about it until the latest round of engine work, and so I just replicated the bodge this time too. I’m not expecting to pull the engine again any time soon, so it seems like a reasonable course of action. 

Oil pumps were also carefully measured several more times, just in case I was missing something stupid that was the cause of the big end failure, but every time I measured them, they came up bang on spec, so I just had to trust the workshop manual rather than my gut feeling. A factory of Japanese engineers will always have a better formed opinion than an idiot in a shed. So with the engine rebuilt (again) and reinstalled (again) it was time to run it up to temperature. And I’m glad to say that this went completely without incident. Nothing untoward at all. No smoke, no clonks, no strange whizzy noises. Just that lovely offbeat rumble that the TRX is famous for. The MOT had expired by now, so I couldn’t really take it out for a test ride. Instead, I booked it in for a session on the dyno and a new MOT at Cambridge Motorcycles. Was I nervous? Hell yes. Given what happened the last time I put it anywhere near a dyno. 

Now, with that said, it *did* make an easy 77bhp before the clattery thing- which may not sound a lot, but this is a famously realistic dyno. I’ve seen a few ‘200bhp’ bikes make about 180. And my old TZR made 55 [1], but regularly outdragged other bikes supposedly making 60. And therein lies a lesson – a dyno should be regarded as a comparative, rather than an absolute tool. (Of course, the person with the bike can always be considered an absolute tool). So one wet and windy morning, I hopped on the bike, and rode to the petrol station to fill up. I mused on the fact that the previous tank of fuel had actually outlasted three engines as I continued my journey into Cambridge. The bike felt great on anything more than about half throttle. Tootling around through 30mph limits it was definitely feeling a bit snatchier than before. But that’s the idea of setting things up on the dyno, to check the fuelling and make sure that it’s not running horribly lean anywhere. 

“It’s horribly lean on the needles” said Spike after the first run. And it was – but the lovely thing about the FCR41s is that changing the needles is a two minute job. So over the course of the next three dyno runs, we lifted the needles three notches, and while it was still slightly leaner then I’d ideally like, we’d run out of adjustment and anyway, it was a million times better than before. The torque curve was beautifully flat, and the noise from the Projection Components 2-1 system was truly noteworthy. There was a bit of an oil drip – I think it was from the water pump o-ring. Certainly from that area of the engine. It may have been there forever, as this is the first time I’ve ever seen the thing running hard at a standstill. After three runs, we were done. Fuelling on the mains was spot on. Like I said, slightly lean on the needles, but we were out of adjustment and it was marginal, so nothing to worry about. 

The bike rolled off the dyno, and into the MOT bay where it passed with flying colours. The ride home was lovely. The fuelling was definitely way better on the needles now, and I made a mental note when I had a few bob to maybe look for some different tapered needles to tidy things up that last little bit. And anyway, the bike was originally set up for the Renegade 2-2 system, not the PC 2-1, so it’s hardly surprising that things were a little snatchy. 41mm flatslide carbs and a 2-1 system are never going to be brilliant trying to hold 30mph at 2000rpm. 

So that was it. The original plan, a year ago, to just take the thing off the road for a few weeks for a winter refresh had gone completely out of the window when I discovered the damaged valves, and then the big end let go, etc. It has been a brilliant journey of discovery, and truly made me realise how much I love this bike, as I would have just walked away from pretty much anything else. So, I did the only sensible thing in the circumstances, and loaded the bike and all the spares into a large van driven by my mate Jack, and sold the whole lot to him.

Ready for the next installment?


After riding James’s 675R at Cadwell a few weeks ago, I knew what was coming. I’ve wanted to ride a 675 for ages now, and it was an itch that just needed to be scratched. And once I’d ridden the 675R, I couldn’t just walk away. The same as the first time I rode the TRX, all those years ago, also at Cadwell Park. Besides, I’ve never owned a triple. I’ve had singles, v-twins, parallel twins, v-fours, inline fours. But never a triple. It looks lovely in the photo, but there’s a few little things that bug me. Notably the missing pillion pegs (already have some being delivered), the slight mismatch in paint between the fairing panel and the nose (it’s been resprayed at some point, and although they’ve done a good job, the pearlescent finish just doesn’t quite match), the ludicrously small number plate, and the shonky levers. The paint, I’ll leave alone – it’s close enough. The levers I’ll change to a set of stock Triumph ones at some point. And yeah, of course, the number plate will be changed to something far less likely to result in a nicking. 

Off to the garage I go then…


[1] I’ve just gone back through my old notes, and actually it made 48. 

I Go Round In Circles

Previously, in Project TRX world, we’d had a bit of a setback as far as the engine goes, but looking on the bright side, I had a lovely new workbench to put my tea on. The engine had done something silly on the dyno and ended up with a floppy big end, and that was the end of part one.

I pondered for a while about the best way to approach this – for sure, it was possible to get my crank reground, but by the time I’d paid for that and a new pair of rods and shells, I may as well just buy myself a new bike. Plan B was just to get a new bike anyway, but I ruled that out for a couple of reasons. Firstly, I love the TRX, it’s seen me through hell and high water (literally – some of the floods I’ve been through on the A505 have been biblical), and is a beautifully balanced bike to ride. But also, this course of action would always niggle away at me as just giving up. So, plan C was hatched. A mate of mine, Orla, had a couple of derelict TRXs in her garage – I knew of them because I delivered them a few months ago. The plan always was that she would cobble together one working bike from the wreckage, and then sell the spares to fund it. However, that never happened, and instead, Orla needed a working bike. A deal was done, and I loaded up the SV650 in the back of a van, and drove down to Kent. A few hours later, I arrived home with this:


Now, in an ideal world, things would have progressed at a leisurely pace from here with a strip and rebuild of the best engine bits. However, I had a bit of a deadline… It was now Wednesday afternoon, and on Friday I was going on holiday, and the day after returning from my hols, I was due at Cadwell Park for the annual Ixion get together. This made the immediate decision very easy indeed. Just pull the engine from one of these bikes, put it in my bike, and hope for the best.

The bike that I chose to disassemble was last owned by my mate Foz. He picked it up cheap from a bloke in Ipswich, with a view to rebuilding it (are you starting to see a theme here… I think it’s a corollary to Heisenberg’s Uncertainty Principle that there can never be two working TRX850s within 250kms of each other) but had given up when he saw just how corroded it was from years in the coastal air. The removal of the engine, therefore, got a bit brutal at times. The exhaust collars had to be cut off with an angle grinder, and there was a lot of leverage (proper leverage, not the leverage that you get in marketing departments) and heat involved to get the mounting bolts out. And the amount of crap that was stuck to the outside of the engine was quite amazing. I literally had to dig some of the bolt heads out to be able to get a spanner on them – the sprocket nut I think last saw the light of day in about 1989 I reckon. However, after an hour or two, the engine was sat on the floor of the garage, and I had a cup of tea to celebrate. The removal had cost me one broken screwdriver, one broken hammer, and one thumbnail sacrificed to the gods of internal combustion.

Tea drunk, thumb bandaged, I started to put the engine in my chassis – and it went in a lot easier than it came out. The tedious task of connecting up cooling, carbs, exhausts, wiring etc. could then begin. This isn’t difficult, just a bit of a chore given that it’s the third or fourth time in as many months that I’ve done it. Finally, about five hours after getting home with the van full of wreckage, I had an engine installed and ready to run. The cooling system was refilled, the battery put on charge, and I closed the garage door. It was too late for a test run, so I really was in the lap of the gods now. Next day, before the long haul down to Cornwall, I quietly pulled on a crash helmet and gloves, and popped out to put some petrol in. It started first time, and although the ride was very short, as far as I could tell, everything was working as expected. Would it survive two days at Cadwell? Heck, would it even get there? I had no idea, and frankly, cared even less. At least I was in with a chance.

And so, 11 days later, I slipped out of the house and stole away at 04:30 to begin the long ride up to Cadwell Park. One thing became apparent very quickly – the carburation was all to cock, running horribly rich on part throttle. No doubt caused by my raising the needles as Spike and I couldn’t remember if it was running rich or lean on part throttle on the dyno, and it was better to be safe than sorry. I made a mental note to drop the needles a notch, and carried on through the early morning fog, arriving at Cadwell around 7am. We’d made it.

Of course, the engine shat itself in the first session on track. I’d like to apologise to anyone following me (sorry Steve…) but at some point the head gasket failed, pressurising the cooling system. This blew one of the hoses, leading to an impressive amount of water being sprayed out of the back of the bike, and oil being spat out of the exhaust. I didn’t care. Really, I didn’t. I was surprised that the engine had got me that far. I dried off my leathers and boots, grabbed a cup of tea, and mused on how lucky I was that the thing, once again, had chosen to fail in a reasonably safe way, rather than seizing solid on the way into Charlies II. This brown study was quickly brought to an end by James though. “Get your leathers on – I want you to ride the 675R”. Now, I’ve wanted to ride a 675 ever since I first saw one. I think they look great, and tick pretty much all of the boxes for things I look for in a bike. And really, I wasn’t disappointed. I spent quite a few sessions on the R, and it just got better and better. Culminating in one last session where I just went completely potty. The first time since I raced that I’ve actually laid it all out on the track, not holding anything back. I made sure I got out at the front of the group for some clear track, and nailed it. Two laps later I was catching the tail enders, and by the time the session was over, I’d grounded out the fairing, and been faster than I’ve been since my GP250 days, for sure. Thanks for the loan James.

The trip home was undertaken in a van with Sol, and for reasons that are far too long and tedious to go into here, James took the TRX back to his, while we took the 675R back with us, necessitating a stop over with Sol on the Friday night whereupon we both got ferociously drunk, so the trip over to James in the morning to repatriate the 675 and TRX was undertaken with a pair of sore heads. Once again, however, the TRX was loaded into the van, and 30 mins later was back home. I had a cuppa, and decided what to do next. As the engine had just blown a head gasket, the easiest thing to do was simply to unbolt the head and barrels, and fit my ones. But, that would really be a half-arsed job. As mentioned earlier, the thing was caked in an impressive amount of road cack, so I made the decision to strip the covers and ancillaries and oil tank too, and refit the ones from my engine. They weren’t perfect, but they were a whole lot better than what was on there. So, engine out again…

This was a fortuitous choice as it turns out. The more I dived into the engine, the more I realised just how bloody lucky I was that it even made it to Cadwell. It had been neglected to the point of almost total dereliction. Every fastener needed heat and penetrating lubricant to move. Several of them needed the rattle gun. Three of them just gave up and snapped, corroded permanently into place by years of abuse. This made it a lot easier to come up with a plan – strip the crank and main bearing shells out, and go for a ground-up rebuild into my old cases. And this is where we are:


The shells *should* match OK, as the numbers on the case are the same on both engines. So in theory, just swapping them over should be fine. I can’t afford new shells or a regrind anyway, so I’ll have to trust my instinct on this one. But the ‘good’ (actually probably better described as ‘less shit’) crank and shells are now in my old cases, along with the balancers, gearbox, and water pump drive gear. Case bolts are torqued up, and everything spins freely with no detectable play in the big ends or mains. I haven’t measured the end float yet. I’ve been too busy drinking tea. The massive pile of gubbins behind is the bits stripped off the old engine. I’m unsure whether to clean these up for spares where I can, or donate them to Tony Robinson for use in a future episode of Time Team. I’m sure they could recover artefacts from the late 1980s in the strata of crap they’re encrusted in.

And that’s where we are. Basically, exactly where we were about six months ago, with an engine in the stand being rebuilt. Again. There is, however, one significant development. Remember plan B earlier? Just get a new bike? I’m now saving for a 675. So when all this is rebuilt and complete, there’s going to be a large clearout of TRX bits to make way for one. I’ve already shifted the VFR and the SV.

I should probably finish this episode with some thanks. James and Sol for the various van rides, and loan of 675s and Katanas, and just good old friendship in the face of adversity. But also, all the Ixies at Cadwell who made it such a great couple of days. Thanks chaps. Same again next year – just hopefully without all the head gasket shenanigans.

Measure By Measure, Drop By Drop [1]

After the last post, it should be painfully obvious that, for want of a better term, the motor is completely rogered at this point in time. It’s not going anywhere with a floppy big end and a bouncy rod. The only thing to do, therefore, is to strip the thing down (again – I think this is the third time now since I started this simple refresh of the valve stem seals…), look for damage, and while I’m in there, see what needs replacing and what can be salvaged. Before I started this though, I did something that I’ve been promising myself for ages. I built a proper solid steel topped workbench, with tool racks on the wall behind, and an engine stand. This isn’t really something that I can somehow cram into the rebuild budget (heck, that went out of the window when I found the first damaged valve, never mind the bottom end disaster) but that’s OK really. Like I say, I’ve wanted to have a proper area for rebuilding engines for some time now. And after a few deliveries and a productive weekend with saws and drills and the like, that’s exactly what I now have.

First task then, was to drop the engine out of the bike. This would have been easy were it not for the fact that I bodged the reg/rec last time and just soldered it into the loom rather than using connectors. Still, no matter, a quick appointment with the wire cutters soon sorted that out. The engine was dropped onto the floor with the aid of a jack, and then lifted into the stand. This was made easier as I’d already removed the head and barrels. With the engine now fully accessible, it was easy to spin it over to remove the sump, and remove the caps to look at the big ends.


First thing for the scrap pile then – the crank. Let’s take a closer look at the rod and bearing shells then:


That’s the second thing for the bin – I don’t even think the rod is salvageable there, as the bearing shell has smeared itself all over the place. Obviously looking at a lubrication failure then, so best take a look at the lower oil strainer to see if we can find the rest of the shell:

20200711_133727 1

Looking on the bright side, at least it appears that the strainer has done its job well, and caught a lot of the shrapnel. There’s obviously a lot of bearing shell there, but also a bit of camchain tensioner, and some green schmoo that looks like some kind of gasket sealant. And while it’s a bit of a hollow victory, everything is completely fine with #2 big end.

While I pondered on what to do next (this involves a trip to see a mate about a couple of spare engines and no doubt some really good tea) I thought I might as well take a look around for other signs of carnage, or any evidence of the cause of the failure. First place to check was the oil pumps, to see if either of them was full of crap, or out of tolerance, possibly leading to low oil pressure. And I’m happy to state that both of them are just fine. Well within spec, and no sign of any bits of bearing shell in there. That oil strainer really did earn its keep there.


As both oil pumps look fine, My money on the cause of the failure is probably a bit of the broken camchain tensioner getting into the crank oilway, and starving #1 big end of oil. I reckon the first, and possibly second mains are going to be in a similar state. And finally, for now, while I’ve got the thing in pieces it made sense to measure the ring end gaps. This is one of those processes that looks like a colossal pain in the arse, but is actually really satisfying to do. The basic idea is that you firstly remove the rings:


Then, smear some oil in the bore, and place the ring in the bore a few mm down from the top:


Using the piston to keep everything nice and perpendicular, push the ring a few cms down the bore:


Finally, withdraw the piston, and using a feeler gauge, measure the gap between the ends of the ring:


Ideally, you’d do this at several stations down the depth of the barrel to check for taper. But in practice, I’ve never found enough to be measurable with my shonky old Halfords feeler gauges. I suspect if I had a proper set it would be worth measuring a few times. Anyhow – the good news is that while the end gaps are right at the limit of spec, they’re not actually out of tolerance yet. This is good, as it means I can rebuild the thing with the existing rings, and then have another chance to strip the engine next year to replace the now worn-out rings.

Right now, things aren’t looking too bad at all – I should be able to pick up a new bottom-end, and then rebuild around that using the posh head with the big valves, and the matching barrels and pistons. But more importantly, I’ve finally got a nice place to work on engines, rather than grubbing around on the garage floor. The workbench was carefully built to be exactly the right height and depth to keep a hot cup of tea within easy reach, so all is well with the world.


[1] Bonus point to anyone who can name the Echo & The Bunnymen song without resorting to Google.

Summertime Blues

Today, according to my googly-wotsit [1], is the first day of summer. A time for celebration, albeit muted in the current global situation of pandemic. But nonetheless, a time to throw those curtains wide, and drink in the morning sun. And so, today, I determined to tax the TRX and give it the first ride since the rebuild. If you remember, last time I wrote about it, the engine had pulled a healthy dyno run, then gone a bit sharty. The stripdown revealed no horrors other than a few signs of a failed head gasket, so it was rebuilt carefully, with new gaskets and a lot of care and attention. I’ve being doing a fair bit of procrastination recently, and as well as that, as I’m looking after my dad I need to be pretty careful about getting out and about too much, and so I’ve never had the chance to get the thing back to Spike to throw on the dyno again. Anyway – I’d know pretty soon how things were going just taking it out for a quick whizz up the road.

First things first, a visit to the site to tax the thing, and without further ado I pulled on my lid, and pressed the starter button. The engine spun lazily, then fired quickly into that lovely off-beat rumble that the TRX does so well. The 2-1 pipe seems to exaggerate this effect – it sounds lovely. The first couple of hundred metres were really just on a whiff of a throttle, tootling through the village at about 15mph, and everything felt fine. However, as soon as I got into 2nd gear and gave it a little tweak, there was a godawful clattering noise. I rolled off, and tried again, just in case I was imagining things. No, there it was again, sounding like a big bag of spanners being carelessly rolled down a steep hill. While being beaten with hammers. I disconsolately turned round, rode home, and threw the moribund turd in the corner of the garage.

To quote another song, ah wus a-wonderin’ wut ah wus a-gonna do.

First reaction was entirely understandable. Beer. However, I had an epiphany. If I was going to drink beer (and by fuck, I absolutely was) I was going to have to earn it. So I pulled my bicycle out of the shed. You see, I do a lot of thinking on my bike. I love the smell and sight of the countryside at bicycle speeds. And when I think I can feel myself slipping into self-pity, I like to go and beat myself up with a hard ride out, which is exactly what I did. And while pottering through The Fens, I started to think constructively, and list what my options were:

  • Just sell the thing.
  • Break it. Sell the good bits, and see what happens with the rest.
  • Buy another engine from a scrappy and throw it in.
  • Make some kind of special, maybe with an MT-09 engine or something.
  • Give the whole lot to Spike for an expert opinion.
  • Do something I’d always promised myself – build a decent workbench, buy an engine stand, and learn to rebuild engines properly.

Not surprisingly, the last option won out. Now that I’m down to a single bike in the garage (I sold the VFR last week – lovely bike, but just not my thing) I can finally make the space to do this. So this will become a learning experience for me, and hopefully end up with a working engine, and a better equipped garage for doing more rebuilds in future.

Of course, I need to pay for all this, and seeing as I’ve just spent a non-trivial sum on the rebuild, that’s not going to happen right now. First thing I’m going to do is just drop the engine, and then throw a blanket over the whole lot and leave it in the corner of the garage for a few months. 2020 will be declared The Year Without Motorcycles in this household. Which, on a global scale, given what else is going on, is hardly going to make front page news anywhere. At least, I bloody hope it doesn’t. But anyway, I still need to have at least an idea of what’s going wrong before I start the stripdown. The clattery noise seems top-endy, but that’s always difficult to pin down exactly, as I’ve heard failed big ends sound exactly like a slappy cam chain before now, so I’m treating that with a pinch of salt. The first dyno run was healthy, and the only thing that changed before the next run was some carb adjustment. I’m 99% sure that it can’t be a carb problem making this noise, but I’ll strip them again anyway, just to be sure. The cam timing was double checked, and the valve clearances all checked out on the last rebuild. The pistons and rings were in good shape, as were the bores. So really I don’t have a clue right now, but it’s something to ponder.

Anyway – I’m feeling pretty upbeat about the whole affair. Which goes to show, there is a cure for the summertime blues:


I love my bike.


[1] Minds out of the gutter, people

Down Down, Deeper and Down

As mentioned last time out, the first run of the newly rebuilt TRX on the dyno had been a bit of a parsons egg really. On the positive side, Spike came and collected the bike and took it away, saving me a journey, and it measured a healthy 77bhp on the very first run, with the carbs running lean at the top and rich in the midrange (or it could have been the other way around now – my old memory isn’t what it used to be). And before anyone starts, yes, I know the book figure for a stock TRX is a claimed 79bhp, but I don’t believe that for a moment. On the downside, the second run produced a lot of smoke, and a less than stellar 60bhp. We had a chat, and decided to strip the engine, and see what was going on rather than risk another run. And in yet further displays of generosity in adversity, I was firstly offered a van for free (Ta James!) to collect the stricken carcass, and then Spike turned up with it in the back of his van anyway. His excuse was that he was on the way to Asda to stock up on beer (sorry, essential foodstuffs during lockdown), so it was easy for him to just throw the bike in the back. Either way, thanks chaps!

So really, thanks weren’t looking so bad at all. Other than the engine oddity, the bike started and ran easily, so the fuel, electrical and cooling systems were all tickety-boo. Spike thought that there may be a problem with the rings, my money was on the head gasket. Both plausible causes for a loss of power and increase in smoke. Either way, it was all the excuse I needed to get the spanners out and have a good look. My main fear, of course, was the new valves. If I’d dropped one of these into a cylinder, that would definitely be game over for this year, as I just can’t afford to keep throwing money at a shite old bike, no matter how much I love riding it. I wasn’t expecting this though, as firstly there were no clattery noises, and secondly, it was still making 60bhp. I really wouldn’t expect that on one cylinder.

I won’t go into excruciating detail about the stripdown, as really it’s just an evening in the garage with the spanners. And while it’s therapeutic to do, it’s pretty dull to describe. I can only imagine how utterly soul-destroying it would be to read about. Rather than that, let’s look at a few pictures of what I found:


And at that, we can all breathe a huge sigh of relief. Me, as it means the valves are in one piece. You, as it means you don’t have to read another 37 pages on extracting bent valves. Seriously though, this was a really good bit of news. Note, however, the difference in colour between the two combustion chambers and valves (apologies, I’d already wiped it over with a cloth before taking the photo). This was the first clue to me that it was a head gasket failure. The combustion chamber on #2 looked nice and clean, while #1 looked wet and brown and sludgy. The gasket had already been thrown in the bin at this point, so I’ll have to dig that out and do some proper forensics on it later. In the meantime, onwards and downwards to the barrels…


Again, apologies for the quality of the photo, but then again, I’m an engineer not a photographer. The barrels look good, for the most part. The honing marks are all still visible, and there’s no scoring to indicate a ring failure, so that’s a good sign. On the not so good side – there’s a hint of some discolouration of the bore on #1 – so maybe there was a bit more water in there than I first thought. But again, this adds to the case for a head gasket failure. Nothing at all to worry about, as literally a wipe over with an oily rag had things gleaming and back to normal. But also, you see that ‘bridge’ between the centre of the two cylinder liners? That’s a water channel, about 1mm deep and maybe 0.5mm wide. And it was completely blocked with scale. Easy enough to clean out, but that wouldn’t have done coolant flow in the area any favours at all, and would actually have led to an increase in fluid pressure exactly where the gasket is at its thinnest.

OK, so head and barrels look all OKish, and free from any signs of a truly mechanical catastrophe. Let’s continue the downward voyage of discovery…


Not much to see in the photo, but I wanted to check that all piston rings were present and correct (they are) and still moved freely in the grooves (they do). Groovy! [1] I’ll pull the rings off and measure the end gaps as part of the rebuild – which I’ll try to document as that’s an interesting and important part of getting an engine running cleanly and efficiently. On the other hand, a new set of rings is somewhere around £120, so unless they’re *wildly* out of spec, they’re going back in anyway. I have standards of tightfisted bodging to uphold, after all.

And finally, on our voyage to the bottom of both the engine and any standards of literacy, I poked around in the crankcase mouth with a torch, to see if there was any sign of bits of metal, eight-balls, or anything else unexpected in the bottom of the engine. Nothing untoward there either.

And that’s where we are right now. I have the head and barrels on my desk next to me, and they’re just getting a bit of a cleanup. Valve clearances should be fine, as Spike set them when he fitted the new valves – but I’ll recheck things anyway, just in case the thing has spat a shim. New head and base gasket will be ordered as soon as I’ve been paid (Jeez, seventy quid for a head gasket?) and then it will be rebuilt and back to the dyno for round 2. Oh, and one last thing to mention, of course, the home-made throttle cable failed miserably on the first real test. I suspect that I won’t be getting the request to go and spanner for Marquez any time soon.


[1] Kill me now. That was dreadful even by my standards of Dad Jokes.

Tremblings Of Trials

Excuse for spelling and grammar: I’ve had a couple of sneaky G&Ts today already. It’s been that kind of a day. While I’m trying not to let the pressure of isolation and lockdown get to me, on a bad day, it’s easy to pour myself a large drink and say “fuck it”. So. Fuck it. That said, all is well – family are all fit and healthy, we have food in the cupboard and a roof over our heads. So all is good.

Right then, that’s got all the horribly self-indulgent introspection out of the way. It’s time for a TRX update:


Phwoooar. I still have a bit of a moment every time I look at that bike. Yup, it’s all back together, and running. The last few steps in this process were all pretty routine really. The drip from the cooling system was of course the rubbish old o-ring that I refitted in the thermostat housing. No worries in replacing that at all – just a bit of a faff given that I’d already had that lot apart once. One thing to note though – the same o-ring is used in Yamaha outboard motors. Identical. If you buy the motorcycle one, it’s £12. If you buy the outboard motor one, it’s £3. (And given some of the weather that I rode through last winter, I suspect an outboard motor may have been more apt anyway). The lovely exhaust was fitted, fluids were added, then I stepped away and left it for a day to make sure I hadn’t forgotten anything.

Next day, fortified by tea, I gave the motor another turn by hand just to be safe. All moved easily, with no apparent crunching or grinding noises. This boded well. I wanted to spin the motor over on the starter to check for oil pressure before firing it up, so the plugs were disconnected, the battery was charged, and I pulled the bolt out of the end of the exhaust cam gallery. Fingers crossed, I hit the button, and sure enough, within about 10 seconds, oil dribbled from the gallery, so oil pressure was good. Given that there was no water or fuel dripping on the floor at this point, there was really only one thing for it. Plugs were reconnected, and the button was pressed.

Within about three revolutions, it fired, and ticked over beautifully. The 2-1 system sounded, um, resonant. But not overly loud actually – certainly no louder than the dreadful old Renegade system. There was a whiff of burning WD40 as things heated up, but nothing to worry about. Once the temperature gauge was moving up the scale I killed the motor, and let it all cool down again before giving the exhaust studs a quick tweak – sure as eggs, they’d slackened off slightly in the first run, which is only to be expected. But otherwise, everything was looking, and sounding good. I gave it another couple of runs up to temperature, ostensibly to make sure that all was well, but mainly so I could just listen to it.

Next step then, was to get things set up on the dyno. But of course, given the whole social distancing thing that’s going on right now, I can’t actually be there to see things. Actually, I don’t mind this – I’ve never liked watching bikes on the dyno. There’s a huge amount of energy being dissipated in a very small space, with the potential for things to go very wrong, very quickly. They scare me. So I happily handed the bike over to Spike, with a cheery wave and guidance that there’s no rush, as I’m not going anywhere any time soon anyway. And today, the results came in. First run, with no optimisation at all, running rich at the top and and slightly lean in the midrange was 77bhp. Now, the important thing with a dyno is to use it as a comparitive tool, not worry about the absolute figures. I know this dyno well – my old race TZR made 48bhp, yet regularly outdragged other TZRs supposedly making 55bhp. So it’s important not to get hung up on the figures. Rather, look at the shape of the curve, the area under the curve, the composition of the exhaust, and the temperature, all in conjunction with each other. So we had a good solid figure, to start with. Things were looking very positive, with scope for a lot more to come.

Next run was 60bhp, with a bit of a smell of burnt oil.

This wasn’t really in the plan at all, but I’m not disheartened. If it can make 77bhp on some fairly iffy carb settings, obviously with something about to give up the ghost, oh, and we’ve not even plugged in the programmable ignition yet, that’s a solid start in my book. Next phase of the development then is obviously to buy an oscilloscope. Once I’ve done that, I’ll be dropping the engine, and stripping the heads and barrels to find the problem. Could be a ring gone walkabout, in which case, that’s all the excuse I need for a rebore to 878cc. Unlikely to be anything terminal with the valvetrain, as it was still making 60bhp – there’s no way it could do that on one cylinder if it had dropped a valve. Could even be something as simple as a failed head gasket – in fact, that wouldn’t surprise me at all. Watch this space.

Now, about that oscilloscope…


These are strange times for all of us. And obviously, I’m looking forward to getting back to some sense of normality with my family – but that’s looking like it’s a good while away yet. One thing is for sure though, I will never take my freedom for granted again. That said, while I’m isolating myself at home, it does give me some time to get on with the TRX rebuild, and also some time to write about it. And now that I have more time, I’ve also gone a little bit further with a couple of things than I was originally planning.

The rebuild really started with the head. As mentioned previously, I’d dropped this off with Spike to get the valve seats recut and a general bit of porting and tidying. And a few days back before the lockdown, I popped over to his to pick it up:


Phwoooar. That looks good enough to eat. It’s certainly clean enough to eat off. Spike really has done a bloody good job there and it’s all shimmed and has new stem oil seals. In other words, ready to bolt straight on. Which is pretty much exactly what happened. I took the opportunity to strip the middle layer out of the head gasket, which is only 0.2mm, but it’s essentially something for nothing, so worth having. The head was torqued down onto the barrels, and the cams given a smear of grease and engine oil and slipped into the journals and the caps installed. Oh, and worth mentioning, the galleries for cam lubrication were primed with a squirt of engine oil, so it wouldn’t be completely dry on first start. Well, it wouldn’t be anyway as I’ll spin it over a few times to get oil pressure before trying to start it, but it can’t hurt. The ceremonial Timing Of The Cams could now begin. This always seems to be a git of a job on the TRX for some reason – I suspect incompetence on my part if I’m truly honest. But after a bit of a struggle, and a bit of skin left behind the cams were nicely lined up as per the workshop manual, and everything torqued down. The last thing to do is fit the tensioner, and this is an absolute pain in the arse with the engine in the frame. Note to self – next time, just take the engine out completely. It’s way easier in the long run. With everything installed and lined up per the manual, I gave the engine a couple of turns by hand to check there was no unexpected valve/piston clouty shenanigans going on. There wasn’t, so I lined up the timing mark on the crank, and checked the cam timing again, just to give myself that warm glow of a job well done.  Of course, at some point in the installation, the crank must have moved, as both cams were now one tooth out of time.


Nothing for it but to take the tensioner out, pull one of the sprockets off to give me room to wiggle the chain off, and re-time everything. Second time around, it all went back perfectly, so I left it alone for a day, and went back next day just to check it all again to make sure, and yes, everything was properly lined up this time around so I rechecked all the torques on the caps and sprocket bolts and popped the cam cover on.

The cooling system was next. I thought it would be wise to check the thermostat, so I pulled the housing apart and gave it a quick test in a jug of hot water. And while I couldn’t get a particularly accurate temperature measurement it was definitely opening and closing in around the right temperature range. That ascertained, it went back into the housing, and it all went back together again easily enough. I decided to reuse the old o-ring in the housing as it looked and felt perfectly good.

No doubt you’re already ahead of me here…

The radiator was refitted with no drama, the hoses reconnected, and everything bolted up and temperature sensors reconnected. I could have refilled the coolant at this point, but decided against it, as I really wanted to get the carbs on so I could run the new fuel and vacuum hoses. And of course, because I’d been so thorough on the cleaning up of the cooling system, there couldn’t possibly be any leaks that would entail having to remove the carbs again so I could get to the thermostat.

Of course not. That would never happen.

Next thing then – refitting the inlet stubs. Really nothing to write home about here – it’s just a case of bolting them up loosely, then feeling inside the join between the stub and the inlet tract to make sure everything is lined up perfectly, and nipping the bolts up. With the stubs now fitted I could make up the new vacuum lines to run to the fuel tap and pump. Rather than pull both lines down the right hand side of the bike, I’ve taken one down either side of the engine, so there’s less of a curve for the r/h line to the fuel tap. It really shouldn’t make much of a difference, but if there’s less chance of it kinking, that means less chance of an inopportune lack of fuel when passing an HGV on the A505. A small change, but one that’s worth making I reckon. The carbs were popped on next to run the lovely Tygon hose from the pump to the inlet spigot.

I could then refit the throttle cables and clutch cable. I was happy to do all this work before refilling the cooling system, as remember, there was no way that anything could possibly leak, necessitating pulling it all apart again.

The exhaust system was next on the list, but I can’t fit this finally yet, as I need a couple of gaskets. No worries though, as I could easily just nip it up in place to see if everything fitted. And of course there was no drama there at all. As this is a 2-1 system I’ll only need one can, so I pulled one of the Renegade cans out of the loft and offered that up to check fitment. All good there. I’ll try to get a photo as it’s so lovely and tucked in compared to the old Renegade system. The link pipe runs pretty close behind the r/h footpeg, but I don’t think that’ll be a problem – we’ll see.

All of that happened during evenings over the past week or so. Today I had time to get out to the garage to make sure that everything was in order, and to refill the fluids in readiness for the final fitting of the pipe and the first start.

Drip. Drip. Drip.

New o-ring for the thermostat housing is now on order.

In other news, this turned up:


It’s gorgeous. It’s the link rod for the gear shifter mechanism. The old one was cracked axially at the ends, and while it would have worked a while longer, I thought it prudent to replace it. This one was machined by my multiple-beSpondon’d friend Rich from a vague description that I mailed to him. It’s utterly perfect in every way. And I can’t wait to fit it, once the chain is on. It really will be a suitably perfect finishing touch.

So it’s safe to say that we’re nearly there with this rebuild. And what started out as a simple refresh all got a bit more complex when I found the valve disaster that was about to happen. No worries though, as with some enthusiastic bodging and corner cutting, I’m still just about on budget. I’ve got the figures all typed up somewhere, I’ll publish them soon. One thing I’ve learned though. Don’t cut corners on o-rings.

Actually, there’s two things I’ve learned. The second is the most important. I really really enjoy building up engines, as should really be obvious to anyone who’s read this blog previously. With that in mind, once things are back to that normal state, and I’ve taken The Lovely Faye out to dinner, and had a day at the seaside with the girls, and been out for a bike ride for the sake of it, I’m going to start earnestly making plans for a proper workshop in the garage.

Finally, to anyone out there still reading this – and most importantly of all. Stay safe at this time. Look after your loved ones. And look forward to the day that this is all behind us and we can play in the sunshine once more.

The Pipe Dreams of Instant Prince Whippet

A bit of a delay since the last exciting installment, and a very simple reason this time. I ran out of money, catastrophically and completely. Not kind of feeling a bit skint in that I couldn’t afford a nice bottle of Aligoté to go with the Sunday dinner. No, properly wondering how on earth I was going to pay the mortgage. Just one of those months when a lot of things happened at once. So the first thing that I had to do was let Spike at Cambridge Motorcycles know that I wouldn’t be able to pay him for the head work, so best just pop it all to one side for a few weeks. Which was immensely frustrating, I suspect for both of us. All that said, things have been going on in the background, and now that I’ve been paid, things are definitely moving forwards again. And so without further ado, here’s a quick rundown.

Engine: Original plan was for Spike to recut the valve seats, give everything a good seeing to with the Dremel to smooth out the ports, fit new stem oil seals, fit and shim the new valves, and skim the head to raise the compression a nadge. Here’s a quick preview of the old vs. new valves:


However, there’s been a slight change of plan there. Because we don’t know the valve to piston clearance with the new valves, and because the new valves are flat not dished, and because it only runs on super unleaded already, I’m not going to touch the compression at this stage. Well, maybe do the trick taking the middle layer out of the gasket, but that’s only 0.2mm. Once I get the head back I can measure the valve to piston clearance with the aid of some strategically placed plasticine, and that can then feed into the next phase of engine development. Did someone at the back say lumpy cams? Go straight to the top of the class if so. There’s no immediate plan for these – but if I can get a set at a good price in future, well, given that I’ve got the flowed head and big valves and programmable ignition, it’d be a worthwhile mod I reckon. But that’s all way in the future. Right now, the plan is to get the engine back together with the flowed head and new valves, and then I can bolt on the new exhaust…

Exhaust: Remember last time I said that I had a lead on a nice Projection Components 2-1 system going second hand? I’m happy to report that it’s now in my garage. And even better than that, the seller gave me a hefty discount on the amount I was willing to pay. It came complete with what looks like the most shatteringly illegal end-can I’ve ever seen:


I’ve no idea yet what I’m going to do with that. Maybe flog it to a local lad to put on the Vauxhall Nova. There’s no way it’s going on the bike, that’s for sure. I like my neighbours too much for that.

Leccy bits: A general tidy-up of the loom really, nothing serious to worry about. Well, other than the connector to the reg/rec getting a bit toasty:


For now, I’ve used some pre-insulated crimps to wire the reg/rec straight into the loom. This isn’t ideal, I know, as it means when it fails I need to cut it out, making more work. But, as I’m resigned to this happening anyway, there’s no point in putting a posh connector on the end of it only to throw it away later. I will keep an eye on the new crimped joins though, just to make sure that they don’t go the same way as this connector did. I’m hoping that I made a good enough connection that I don’t need to worry about it.

Fuel system: Finally, I’ve ordered a complete new set of fuel and vacuum hoses. This is something that really should have been done in the initial restoration, but I’m tight and lazy, so didn’t bother. So there’s some Tygon hose to run from the pump to the carbs, and a genuine Yamaha bit to run from the tank to the pump. And if I ever find the person who designed it so that the fuel tank outlet is a different diameter to the pump inlet, I’m going to punch them right up the bracket. I shouldn’t be surprised really. In my experience, Yamaha have never designed a decent fuel system. New vacuum hoses to run from the inlet stubs to the fuel tap and pump complete the work here.  Carbs got a good stripdown and clean, and everything appears OK in there.

Odds and ends: General clean up, brakes now all bled and seem to be working just fine. New chain from the marvellous Alan Russell is now sitting on my bench beside me, waiting for an appointment with the chain tool and Big Hammer. Large scratch put in fuel tank by me being a catastrophic pillock. MPH speedo refitted.

That’s kind of where we are right now. I’m not going to do anything cosmetic to the bike at this stage, as it’s still very much a working bike, which will get used again in all weathers. So no point in spending a ton of money that I don’t have just to make it look nice. No. Not at all. If I do come into some money in the near future, I have other plans for it. I would have to come into an awful lot of money though – as it’s a Spondon frame that’s currently for sale. I suspect this is just a pipe dream though – there’s only three of these frames in existence, and I’m sure that it will be sold by the time I’m anywhere near being able to afford it.

On the subject of which, the SV650 that I wrote about here is now very firmly up for sale. If you’re interested, let me know. Any funds raised go into the Spondon piggy bank.