Heathy, have you solved it? Was it an airleak at the carb?

I covered up the leak with some fibreglass resin and hardener (first thing I found) and it does seem slightly better but its still doing the same thing only now the slide can open slightly more before it does it.

The slide moves smooth and I have never altered the float hight

I tried the propane method today and it calmed the bike down slightly, I also noticed black liquid (probably oil) started spitting from the exhaust, but I guess this would be normal as the propane is making the bike run rich.

I put some gasket seal around the oring at the top of the carb because it seemed to be leaking from there, now the bike seems fine when im riding it but will rev like mad when its either out of gear or the clutch it pulled, it seems as though the engine is now only over reving when it has no load on it.

Sorry I forgot to mention, I did have the bike pressure tested and it has no leaks

I've been trying to get hold of another carb to test it, as there are not many riders around this estate (that I know of).

It seems to be fine now when the engine has a load on it but when it is free from the gearbox it starts reving like mad

Edited April 12, 200521 yr by Heathy

Alright...I hate to say the simple/stupid thing at this point in the discussion, but.....

Are you sure there is really something wrong with this bike?

A motor with no load will rev really high with only small throttle openings.

You mentioned 5mm. That's enough to make it really rev high.

How does the bike run while riding?

You seem to be talking about what it does at a standstill.

Sorry if I'm asking stupid questions while you're pulling your hair out, but I'm not totally clear about what's going on.

Standing still you open throttle and if you twist the throttle only a fraction in nuetral it revs its nuts off, but in gear you can blip it and its normal?

All with airbox in position?

Im just worried about siezing it up again because its very expensive to fix, I know it is normal for it to rev high when out of gear but it seems to rev a lot higher than it used to

This is bugging me so much I am temted to go to teeside.........then again

Lol ...its bugging me too dabster, I know it should rev high with no load on it but it used to have a point (as with all 2-stroke engines) of maximum revs where you know you can rev it there for about 10 seconds and wouldn't expect it to sieze. At the minute I wouldn't even dare take it to the top of the rev range.

I've worked on 2 stroke engines for around 8 years and my dad has worked on them for around 30 and neither of us can find the problem

I want to know what the problem is now no I havent changed the carb yet as I don't know a lot of riders in the area, a few of my mates have bikes but there crossers

Did you split the motor when you did the rebuild?

Did you do the pressure test?

Yea I split the motor and reassembled it with all new gaskets and a light coating of grease on the gaskets. It has been pressure tested and has no leaks. The bike had this problem before it was rebuilt and is the reason i had to rebuild it due to a siezure. I think the only think left that it can be is the carb now