I've got my TY250C coming apart for main bearings, seals & a rebore to 1st oversize & want to know is there any way to improve the action of the clutch while the engine is in bits.

The basket & hub are in good shape but I found the clutch to have very narrow range of engagement almost like a lightswitch which is a problem when making full lock 180deg turns as found in modern clubmans sections

Levers are domino trials & the cable is a new venhill, action is quite light so I don't see any problem there

Any suggestions or is this how they are?

No they are a very good clutch if working properly

Things to check:

edges of basket fingers need to be completely smooth not ridged

steel plates need to have a rough finish (not polished smooth)

cam surface smooth

end of pushrod smooth

newish friction plates (originals would have lost their frictional properties by now)

suitable oil in good condition

I also run Domino levers and Venhill cables on my TY250,but as David says if they are in good condition they are a very good clutch.I have lengthened the operating arm by about 15mm on mine and have fitted an angled cable seat to make the cable pull in line.This works very well and apart from a little freeing off when cold its perfect.I use Land Rover MTF94 oil in the gearbox,(I run a land Rover garage....) which keeps the box clean and does not change its properties when hot.

If you need Cluchfriction plates,Yamaha XJ 550-900 are the same as TY 250

Cheers:Mike

The adjuster was wound way in & has a flat worn on the outside, looks like the ball that sits between the push rod & the top hat piece that pushes on the pressure plate was missing, does anyone know what size it should be?

The cam is fairly flat with a small mark on 1 side which I'm picking will be out of the way when there is a ball back in the system taking up the slack & the adjuster won't be wound in as far. Not sure about the flat on the adjuster but I'll have a look to see if a new 1 is available

Looks like TYtrials has the adjuster so I'll put another order in this week

Edited March 19, 201313 yr by tony27

The ball is the same diameter as the rod whatever that is (5mm maybe). You can file or grind the face of the cam flat again, just make sure it ends up smooth where the rod end contacts. I've successfully built worn ones up with mild steel weld and machined the OD back to size when the pit in the cam was too deep. I don't think the cam face needs to be especially hard, but smooth is important

Edited March 19, 201313 yr by feetupfun

Looks like the ball will be quite a bit bigger than 5mm, the hole in the end of the mainshaft looks closer to 8-10mm. Will measure the hole size & fit the nearest size ball that I have, if it was too small the pushrod wouldn't make contact properly

Have come across another puzzle when stripping the motor.

The parts lists show a shim of .3/.4mm between the main bearing & seal on the clutch side of the crank, my guess is it spaces out the primary gear to a set amount. I didn't find 1 in there & wonder what effect not having 1 fitted will have

Any thoughts?

Have started assembling the motor but cant work out how the spring that sits around the actuator sits, the square end obviously fits over the lever but where does the round end go? My manual doesn't have a clear shot of how it should be

Can anyone take me a photo of their bike to show the setup?

This is a B model bottom end. I looked at an A model as well and it looked very similar

Thanks David, I did suspect that was how it should sit but thought there had to have been something I was missing.

Hopefully I should be able to finish putting the motor back together on thursday