So after some light restoration of my sons ty 80 I've bolted it all back together , gone to start it and the revs are sky high , all the setting are correct , it seems like it may have anoticed air leak or something of that description. It doesn't seem to matter what I do to the carb it does not seem to make much of a difference, the annoying thing is I didn't touch the engine or carb all I did to the bike was a light cosmetic clean up can anyone help please ?

The throttle cable isn't sticking is it inside the cover ?? Stupid as it sounds it happens

Nope I've checked and checked again I still can't see a single thing wrong

slide in backwards?

Slide it backwards can you please elaborate?

So I'm contemplating fitting a new carb can anyone suggest what one to put on it , could I try something like a cg125 carb with different jets maybe ?

I seem to remember the port on top of the inlet manifold was prone to dropping off causing a massive air leak and the assocated screaming engine.

 

Methinks it was the engine oil transfer port from the autolube system that usually get removed (and the port blanked or bunged up).

Check it isn't sucking in air from there.

Edited November 10, 201510 yr by goudrons

Checked and even machined a nice new plug and glued it in

Have you had the carb apart and checked it all over? I have had a carb where the needle and needle jet had got very worn and could on occasion hook up and effectively jam the carb.

If you are reasonably mechanical and have acces to a lathe you can make a leak test kit quite easily. This will at least answer the question about a leak.

No reason why you couldn't fit a CB carb if you changed the jets to suit. Personally I would of thought it would be easier to try a carb off 50 or 100 2 stroke road bike as you could probably go with it straight away.

Slide it backwards can you please elaborate?

It is possible to put the slide in backwards. Do you know what the slide is? I`ve seen this happen a dozen times. Back to the carb, take the top off, the angled cut goes towards the filter. Simple.

In my opinion it's only possible to put the slide back in the correct way as the other it clearly doest sit correctly, I've now found a small crack just to the side of the mixture screw , so I'll replace the carb and all should be good