feetupfun

If you are talking standard bikes, standard TLRs are about 10 years worth of bike development better than standard TLs. Where I ride, twinshock class trials machinery is pretty much carte blanche. With enough effort and know how, you can make a TL125 go just as well as a TLR, and people do. The performance limitations in our twinshock class come from having to have drum brakes, twinshock rear end and a motor that originally came from a twinshock motorbike.

no idea. It's a pain to do it too. I can only remember the number from one of my twinshocks. The rest I have to go looking with a torch. Maybe I should make a list. A friend of mine who also rides multiple bikes confessed last weekend that he just makes up the numbers each time "because no-one ever checks them anyway"

Sorry for not being Guy, but all over the world people remove three of the clutch springs on TY250 twinshocks to lighten the action

Frame and engine numbers on entry forms for trials competitions has been standard practice in Australia for as long as I can remember, but I don't think anything is done with the numbers

The body of the silencer is the same (250 vs 175) but the inlet pipes are different length and shape

My WES end mufflers on TYs are quieter than stock too

Modern internals vs modern forks makes no difference, but fork visuals are important to me. As for the motor, there are potentially important advantages from using a later motor, such as less weight, less width and less length

The last video looks like how a standard Ty250BCDE in good condition responds. The standard motor has a strong flywheel effect that most people didin't like when they were new and the same sentiment applies even more nowadays with grippy tyres and good rear suspension. Lightening the flywheel is a very common mod to these engines. Another beneficial mod to make them more snappy is to fit a good modern ignition.

How about a photo of what you are talking about

Make or find a puller that doesn't damage the gear teeth. The usual two or three arm puller will likely not be able to pull hard enough and will damage the teeth. A suitable puller will pull against the back side of the gear without touching the teeth and it will pull on the whole surface, to spread the load better. I made a tubular puller that is in two halves. There are discussion threads on this forum that cover this job in detail. I can do photos again if the thread has disappeared.

I will be interested to see if you still think it is easy to work on after you get the primary gear off

you've probably sheared the flywheel timing key

I saw the other side via some other photos which were posted on Facebook. I saved the photos and will post them up soon

It's normal for a 4 stroke to have a strong on/off effect with the throttle

My 348 used to have a positive pressure inside the clutch casing. I was never sure that it was a crank seal causing it though because I cleared out the gearbox vent (which was blocked) at the same time that I changed the crank seals.

Despite being Australian, I've successfully interpreted billyt previously and will now have another go: If you ride those three trials with the strange names, the terrain at these trials will suit a trials bike with a fast throttle response

https://www.tyoffroad.co.uk/store/p40/TEMPORARILY_OUT_OF_STOCK.__FOOTREST_LOWERING_KIT_(BOLT-ON)_TO_FIT_HONDA_TLR200._(REF.H025).html

What did the gearbox oil look like?

Not a big deal. A common sight on a trials bike that has ridden a wet trial. I would just fill it with fresh oil. Next time you ride in water it will probably do it again. Sometimes wet oil affects the action of the clutch but if you didn't notice, then I guess yours doesn't get affected.

Easily proven, as I did for myself, by putting a paint marks on the tyre and the rim. Go for a ride starting with a straight valve stem. Look at it after the ride. See valve leaning over and pulled hard against one side of the hole and yet the paint marks are still in alignment. I admit to doubting that this could occur so that's why I did the experiment

Yes the tilting valve stem on a trials wheel is often misdiagnosed as tyre slip. Sometimes fitting a different brand of tube in the same tyre will stop it happening

Sounds like you are thinking of a 5 speed Bultaco engine rather than the Yamaha TY250 motor he is working on.

I love the clutch spring story. It reminded me of when I was working on a TY250 kickstart a couple of years ago. The tiny spring that pushes on the ball went "zing" over my right shoulder at high speed and out the tilta-doorway to somewhere on the rough ground behind my workshop. I looked for about 10 minutes but they are tiny and it would have been coated in dirt so I gave up. A few months later my wife (who knew about the spring incident) gave me a metal detector for my birthday. Well I had a ball finding the most amazing variety of small metal objects out the back of my workshop, but no kickstart spring. I was telling a bloke at work about the spring story and was pleasantly surprised when he later gave me one of those springs that he had ordered along with a swag of other TY parts for a bike he was fixing up. This searching business in a crankcase also reminded me of when I first pulled the cylinder off an OSSA motor. The cylinder studs are usually rusty and if you do it the normal way up there will always be rust particles fall into the crankcase as the cylinder comes free. To avoid this, I hoisted the bike up in the air, upside down, so that when the cylinder moved away from the bottom end, the rust would fall away from the crankcase

I must say I'm impressed with your workmanship, especially the fuel tank. Making stuff yourself is very satisfying. I've wanted to try making an aluminium trials bike tank for a while and seeing yours is motivational. Back on the rules. Over the ditch, we've got a manufacturing date cutoff for "twinshock" bikes (1 Jan 1987) which would be a problem if you wanted to ride that bike competitively over here. Apart from the rules there is always the "pub test". Not sure if this happens in other countries but it definitely is a thing here. Years ago TV reporters doing an opinion piece would posit "what would the man in the street think?" The official legal term is "what would a reasonable person think or do under the circumstances?" But the "pub test" sounds lots better to me because with any luck, she or he will have had a few drinks and be quite prepared to share their thoughts about any topic. I haven't had a drink tonight so I'm probably not the right person to be sprouting off one way or the other.