‘the more tools you have, the more options you give yourself when you face a new problem’
Horace Walpole apparently enjoyed enough happy coincidences in his life to invent the word ‘serendipity’ to describe them back in 1754. You might say serendipity is the flip side of the generous dollops of Sod’s Law we all endure while working on old motorcycles – and although less common than its evil twin, I enjoyed a little bit of it this month while busy finally sorting out my TriBSA Scrambler – you know, the one I built in CB a few years aback and, er, never finished. One of the many issues was the oil tank. The breather had been sawn off the top, leaving a drilled hole which would provide an easy ingress for water. An old brake pipe with a right-angled fitting looked like it would make a tidy breather hose and luckily I found a double-ended union that would couple it to the tank – if I could find a way to get a nut on the back. Result! I found I could just reach a finger inside to screw on the nut, but there was no way I could tighten it. Hmmm... Trawling through my spanners seeking inspiration, my eye fell on an old open-ender bent to access some long-forgotten job in someone else’s career. Not only was it the correct 9/16in AF size, it was bent to exactly – yes exactly – the right shape to access the nut inside the tank through the filler neck. Now that’s serendipity for you! Or is it? Minimalists and tidy workshop fans would be horrified at the amount of junk I have carried through my life, from shed to shed, but as I see it the more stuff – tools, parts, bit of metal, nuts and bolts etcetera – that you have, the more choices and options, you give yourself when you face a new problem. Increasing your options is a way of making your own luck. Its probably true to say that I will never need 90% of the stuff on my shelves – but it’s the other 10% that makes it all worth keeping.
The Big Fix
Several suggestions for a tighter, rattle-free fit for a Triumph front brake
Phil Lou emails to ask for advice concerning the sloppy fit of his Triumph front brake. The anchor lug on the fork fits into a slot in the alloy brake plate; over time the slot wears and although it isn’t really a safety issue (the lug can’t come out), it is annoying and tends to rattle at tickover, only stopping when you apply the front brake. Phil says he’s concerned about distortion if he has the plate welded, so what about welding extra material onto the fork lug to take up the slack? Well, the most pragmatic solution I’ve seen was on a mate’s BSA A10 – a broken hacksaw blade was wedged in the gap, the hole in the end lashed to the fork with a twist of wire. It worked perfectly, but assuming Phil wants a more aesthetic solution, I would go for having the plate welded and remachined. I doubt the amount of weld needed would be enough to distort the plate and it is generally better to put right the faulty part than modify others to suit – maybe Phil will find a better plate sometime. That said, the fit needs a bit of slack in order to facilitate fitting the wheel; what prevents the rattle is the fit of the large nut securing the plate to the wheel spindle. With the spindle clamped in the fork, this nut acts as a torque stay in itself, locking the plate to the clamped axle. The direction of wheel rotation tends to tighten the nut, but there are two problems: first, if the bike is rolled backwards on the brake, slack at the anchor will try to loosen the nut, and second the nut is difficult to tighten properly in the first place. It needs to be done off the bike, but you can’t grip the spindle adequately in a vice. My tip is to use the two axle clamps as vice jaws. The grip is then good enough to use a large ring spanner. That may be all that Phil needs to do.
Anti-puncture advice and clutch drag avoidance
Foil quality-control label chafed
inner tube, causing a puncture
Here’s a nasty one. Just a couple of days after a spirited ride at Cadwell on his Vincent Black Shadow, Mark Vane had a rear puncture. When he removed the tyre he found a foil quality-control label inside the Avon Roadrider tyre had creased and chafed at the tube. He checked the front and found the same thing. It’s no problem with tubeless fitment, but when using tubes it’s obviously worth removing this label before fitting.
Rudge clutch was a drag, but it
was down to a tight primary chain
Last time out, my Rudge’s clutch started dragging and the primary chain worked tight. Once back home, I set about adjusting the clutch springs for even lift, but I couldn’t seem to get rid of the drag. It took a long time before I realised that the still-tight chain was pulling the clutch basket out of line and taking up some of the lift. Okay, you may say that it was a bit of a dumb mistake on my part, but it’s entirely possible that the spring tensioner on a unitconstruction primary drive may create a similar effect.
Stale fuel tale
Bob Harris from Telford has a Canadian import Kawasaki KZ440 LTD and finds that if it’s left standing for a week or more it takes five or six goes on the button before it will start – but if he puts the tap onto ‘prime’ for a couple of minutes first, it starts easily and is fine until left standing again. With a vacuum tap as on Bob’s bike, the tap is automatically operated by suction from the inlet manifold. The ‘prime’ position is just a conventional ‘on’. If the fuel is evaporating or leaking while standing, it will take a bit of turning over before the vacuum tap has been open long enough to refill. Opening the drain screws on the bottom of the carbs before attempting to start will reveal if the float bowls are empty. Alternatively, it may just be that the fuel is a bit stale. Modern petrol goes off very quickly – but bearing in mind that the stuff in the tank will stay fresh longer than that in the carbs, turning to ‘prime’ may just get the fresh stuff in there a bit quicker. I also wondered if, being essentially a US model, the mixture may be tuned leaner than an equivalent UK model, which can affect slow-speed running, starting, pick up, etc. But Bob came back to me to say that after draining the carb, the bike was back to normal.
Source of Trouble
Bill Brown’s 1984 Kawasaki Z1100R starts and runs okay, but after eight miles or so it starts cutting out one cylinder at a time then stops, as though he’s run out of fuel. Left for 15 minutes it starts again, but eight miles later it all happens again. He’s replaced the plug leads and coils and checked the fuel system. “I even ran it with the tank cap open in case the breather was blocked,” he says. “But no difference. Could it be the ignition pickups or igniter box failing when it warms up?” Well, ignition is the usual culprit and first I’d suggest carrying a spare plug so that when the bike cuts out you can just stick it in a plug cap and wind the bike over with the metal of the plug grounded to earth – it’s a quick way of checking whether or not you have a spark before it gets a chance to cool and recover. I had a word with Luke at Rex’s Speedshop (01580 880768) and although he’s not aware of any particular issues with these bikes, he said the symptoms indicate failure of the source coil in the generator. If so, this is something Rex’s can replace. They can also test (but probably not repair) the igniter box. Luke says at 40-plus years old it’s not unusual for the pickups to fail, but this is less likely to be related to engine temperature so the source coil is still the prime suspect.
Make a DIY thread repair insert
Helicoils are a good fix for stripped threads if you have them, but if you have a lathe you can make your own inserts
Tim Weeks needs to get a V5 for his Yamaha SRX600, but while on the DVLA website he came to a halt with the request for the number on the VIN plate. “I can’t find one on the bike,” says Tim, “So how am I going to get it registered?” Presumably someone has removed the plate to repaint the frame and not replaced it, but since the frame number is stamped on the headstock anyway, why does it matter? I rang MoT tester Dave Massam who agreed that the VIN plate is not part of the test and he can’t see why its absence would be a problem, as long as the frame number is visible. I suspect the wording on the DVLA site is confusing. Obviously you need a frame number to get a V5, but the instruction probably applies to cars, where the VIN plate is often the only easily-visible chassis number. Okay, the plate carries other information besides the number and may be important in the case of licensing restrictions on bhp for learner /novice riders, but I can’t see it being necessary here. I contacted John at vinplate. co.uk (07831 276655) who manufacture replacement VIN plates for restorers. John reproduces a range of plates and although he agrees it probably isn’t necessary to obtain a V5 in this case, he suggested Tim contact him if he wants one to add the finishing touch to the rebuild.
Roy Houghton adds his story to the ‘are old helmets still legal’ question (Fixes July). A few years ago he was riding wearing an Owens Skulgarde (a helmet disguised as a flat cap) when he was pulled over for not wearing a helmet. He pointed out the helmet’s kitemark, but as the police record didn’t list BS2001/56, he was arrested and charged. Roy appealed to the Prosecution Service with letters of support from the VMCC and BMF and later received a call of apology from his local Police Inspector to the effect that the case had been dropped as their records had proved incomplete and Roy’s helmet was indeed legal. Roy says he wouldn’t wear an old helmet now and since this incident occurred a few years back it’s possible that European laws may have had some influence since.
another job on the list...
It’s a case of one problem fixed but another raising its head as Rick prepares for his annual pilgrimage to the Island
Back in the dark ages, I used to dread breaking aluminium components. I couldn’t fix them and I didn’t know any aluminium welders. Then I discovered Lumiweld. It’s been around a long time now, and even though I have sort of mastered aluminium welding with my MIG machine, I still return to Lumiweld for anything delicate. This month I needed to make inlet stubs to fit the twin carburettors onto the Martinsyde’s new 750cc top end, ready for the trip to the Isle of Man later this month. I have two differing carbs: one is clip fitting, the other flanged; I decided the way round this was to make two stubs the same and then just Lumiweld a flange to one of them. Having run out of rods, I ordered a kit from Frost (frost.co.uk), going for the ten-rod kit at £20, which seems a bargain at just a fiver more than the five-rod kit. It was a quick and easy job with oxy-acetylene, although it works just as well with propane – it just takes longer and you can speed it up considerably by creating some sort of hearth with bricks to retain the heat. Perfect; after putting it all together, the bike started easily and I tested the pickup with the application of a few revs... “PHAT!” A huge chunk of head gasket blew across the workshop. Dammit! Oh well, back on the bench with the Martinsyde – but at least the carbs are on now.