feetupfun

About the tab washer, yes this mode of failure is more likely because the tab washer connects the sprocket with the nut, making it more likely that the nut will move relative to the shaft. However even without a tab washer, the nut may still rotate with the sprocket when it slips on the taper

If it was me I would let TALON know about you issue. If the problem is the coating on the bore of the sprocket, it would only cause problems with bikes that use a taper mount sprocket, and there are very few bikes that use a taper to mount the gearbox sprocket, so they may be unaware of the problem.

I think you are right about the nut becoming tighter when you ride, causing the taper to break the sprocket. The only thing that can cause the nut to rotate relative to the shaft while you are riding is if the sprocket spins on the shaft, so maybe 50 foot pounds is not enough to prevent slippage. I see that the sprocket came with a yellow coating which may affect how well the sprocket locks onto the taper (the angle of the taper is designed for steel/steel contact)

I have that gearbox output shaft arrangement on my 348 and have not had a problem with the sprocket splitting or slipping. My sprocket is a TALON purchased in the 2000s. Some thoughts came to mind when I read your post: Maybe faulty sprocket (possible incorrect heat treatment process) Maybe a lubricant was used on the taper during fitting of the sprocket A clear photo showing the fracture surfaces of the sprocket should show if the problem is a faulty sprocket.

I remember from apprenticeship college having to make a square plug about 25mm long and 25mm across the flats from a piece of round and a square hole in a piece of flat plate all with hand tools and it had to fit perfectly all eight ways and all the way along. Lots of filing in that one

Yes there is not a huge difference in the voltage generated by the lighting coil compared with the LT coil. The ignition might have even worked with the lighting coil in the original position, because there are four magnets and the coils are opposed on the stator plate. I was working on a friend's TY175 and was having a hellova time trying to get the flywheel off. After many hours of heating/cooling it popped off unexpectedly and fell on the concrete floor (the bike was up on a bike workbench so it fell about a metre). One of the four flywheel magnets broke in the impact. Luckily the broken magnet was one that is only used by the lighting coil. I removed the broken magnet and the opposing magnet (to keep it balanced) and the ignition still worked fine.

I don't think that nikasiling the bore would make any difference to how well it ran compared with a fresh rebore. Doing the clutch basket fingers sounds like something that might be useful though

03 is yellow graphics. 05 is red and black graphics. Maybe you could post up a photo of the stator you want to identify.

We have a cut-off date of 1 Jan 1987 which seems to cover most trials bike originally made as twinshocks, but not the much-later RTX

Here is what trials gas girlings from that era look like with the long spring removed Yours look like someone has fitted spacers to limit the shaft travel

Why do you have to choose one or the other? There is nothing wrong with having some of each

I only ride twinshocks but concede that a newby to trials would probably learn trials techniques faster on a modern

http://www.ebay.com.au/itm/Betor-Rear-shock-seals-Bultaco-OSSA-Made-in-USA-/252149753514?hash=item3ab54be6aa:g:FlwAAOSwhcJWNDK5

See if you can nobble the damping on the Curnutts or the Works Performance shocks while you have them apart. Standard they have way too much damping in both directions for trials use. For your friend getting the four original type Betors, there is a bloke in the USA selling shaft seals for them and you can also get the mounting rubbers. I sometimes run them on my OSSA. they are not quite as good as modern Falcons for damping action, but I love the look of them

I've heard the bottom bits (of pre-USD forks) that the wheel axle connects to called bottles, sliders and legs. I've also heard the whole assembly called a leg. I've heard the long tubular bits with the smooth shiny surface called tubes, stantions, staunchions, stantons, stornchons, sliders and legs There is nothing wrong with calling anything anything, as long as the message is successfully communicated. When the initial question was asked, I wondered what the writer meant by "tarnished" I'm still trying to work it out what "tarnished front forks" means to the writer, hoping I can help with the problem

Anodising is a hard coating on aluminium and is a form of aluminium oxide. Some oven cleaners contain sodium hydroxide. Sodium hydroxide solution dissolves both aluminium and aluminium oxide

never heard of a slide with zero cutaway. Is it fitted the right way around?

what part is tarnished?

Did the plates move out parallel? Even with very flat plates, if the springs are not preloaded evenly, the release travel will be long because the pressure plate tilts

The release travel required depends on the sum of the out-of-flatness of all the plates. The fibre plates (outer plates) I've put in one of my Bultacos (Barnett) were very flat and did not increase the travel required. The production method of the original Bultaco plates is stamping, which is a method that by its nature introduces some degree of out-of-flatness (depending on the condition of the shearing edges) It is very common to see high and low spots on used OEM Bultaco plates, which is evidence of their lack of flatness

It is much easier to set the clutch up with the perfect amount of preload on the springs if you replace the clutch inner with one that has threaded rods and nuts for the clutch springs instead of the clutch inner that has the pins-through-holes spring retainers.

Sprocket: The sprocket is on a taper. If you use heat to help it break free it will probably melt the oil seal but if you are rebuilding the motor it probably doesn't matter. I usually cut old sprockets off my 348 with a 100mm angle grinder. Works a treat Crankshaft: Remove the seal holder Warm the casing to free up the bearing outer

A friend in the 1970s ran his almost-new Suzuki Waterbottle (GT750) on straight petrol (with the oil injection system not functioning) for a few weeks of riding to work. He pulled the cylinders off expecting carnage but the top ends were still perfect

A router is flash. I use a hacksaw

Kind-of-porky OSSA MARs and every other twinshock I have ridden go much better with modern tyres than they did with old style tyres