Hi, I have recently been trying to get my old Yamaha YFZ 450 to run again since it had some problems, at first it wouldn't start at all, then I took the carburetor out and had a look at it and messed with some settings, then put it back in the bike and it was starting fine after that, now the problem is, when it starts it idles perfectly fine, but the second I touch the throttle it goes to a high rev and doesn't go down until I switch the bike off. Any suggestions? (I can't seem to find anything.)

 

Hmm. Well its good you got it running. Check your rev limiter, could be something funky with that. Have you try putting tin gear and riding with it reving?