So here goes.

I'm doing up my dad's 2002 txt pro 200 or edition 200, whatever it's actually called.

The clutch casing on it has threaded at the banjo bolt so he bought a replacement casing. Trouble is none of the internal bits transfer over. I know about the 2003 onwards upgrade to it and thought that by getting a 2003 on clutch piston, spring and spring helper the problem would be solved (thinking that the casing was newer anyway). But no! The piston flaps about on the spigot in the casing. 

Internal diameter of the piston is 14.98mm which I'm told is the newer upgraded clutch one, and that the 2002 item was narrower. Yet the return spring and helper fit perfectly in the spigot (see pics). If the piston is the right size yet too loose you'd think the casing is wrong, but then why do the spring and helper fit so well?!

Also the new clutch casing has a part number that gas gas parts finder doesn't recognise.

It's frying my head!

 

Any thoughts?

Would it work if you fitted fatter o-rings onto the existing piston?

... more of a bush fix but o-rings do come in different sizes and all you need is a fit that seals without sticking.

Edited August 29, 20232 yr by lemur

2 minutes ago, lemur said:

Would it work if you fitted fatter o-rings onto the existing piston?

Something I contemplated, going for maybe a 2mm thick o'ring. But I decided against it as I didn't want the piston applying uneven pressure on the clutch spring fingers.

Think it needs to be a snug fit to stop it wobbling. When 'fitted' there's maybe 5mm play at the base where the roller bearing sits

So whats the dealer say that you ordered them from? But it will be a battle as alot changed through the years and the 2002 was basically a proto type as everything was crap at best.

18 minutes ago, lineaway said:

So whats the dealer say that you ordered them from? But it will be a battle as alot changed through the years and the 2002 was basically a proto type as everything was crap at best.

I ended up getting a used part. The piston I got what from the same casing and was smaller internal diameter. So somewhere along the line a supplier has got their facts confused as later year casings ('03 on) are a smaller i.d, not bigger as I was originally told

Yeah, any upgrade you want 05 and newer. 2002 through 2004 was terrible years for the pro engine. No matter who says it. The pro motor when running is an incredible trials motor. It just had many issues to overcome.

Thanks all for your replies.

I eventually found a used top hat from an identical casing. Turns out the info on the earlier clutches having a smaller diameter top hat was guff and it's the other way round. Cost a week of thinking I was going mad 🤔