Posted by Hogryder on April 16, 2001 at 04:48:44:
In Reply to: Engine runs only on choke...? posted by Peter the blacksmith on April 12, 2001 at 20:56:44:
I had a Yammerhammer (Yamaha) that did the same thing. Would only idle with choke, died when you gave it gas. Turned out to be a leaky vacuum line. Replace the vacuum line even if you can't see a crack, it doesn't take much.
If that doesn't work, try removing the air filter and run it unobstructed for a short time. Needless to say, don't ride it in that condition, just try it in the garage. If it runs OK, get a new filter. If that doesn't work, replace the jets, even if they look good. If you don't want to mess with the jets, add about 6 fluid ounces of fuel injector cleaner to the tank and run it as long as you can. If you're lucky it will slowly clean the jets and you will notice the performance improving. When it gets to the point where you can ride it, do so. As long and as far as you can. Keep using this fuel mix until performance no longer improves.
Good luck.