This bike was parked 4 years ago running. I had to put new vacuum pistons on both carbs. Carbs have been cleaned. Throttle cables were untouched. It will start if I put fuel in the cylinders and run until it burns it up. It has all fresh gas and the fuel pump works. The bowls have fuel. It has good spark on all 4 plugs. After starting it by putting fuel in the cylinders it will half start and barely run. If you think about touching the gas it dies. Help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!

 

Assuming the carbs really are clean, and the pilot circuit isn't gunked up any, and the float height is adjusted correctly, and there really is fuel in the float bowls, and that fuel is good, and the pilot/idle air screw is set correctly, my first guess would be insufficent vacuum in the intake manifold.

If you have a vacuum guage, hook it up to the intake vacuum port and see what it's running at. Check your service manual for proper vacuum pressure.

Possible causes: Carb boots are cracked, Carbs aren't seated right, intake gasket is shot, intake vacuum port gasket (generally copper washer) is shot.

 

Thanks project_mercy for the reply. I tore the carbs off and spent another 2 hours cleaning them. Very carefully removing every single piece of build up. Wouldn't ya know it part of the choke system on both carbs was plugged. I had to use pins, wire and other small items to clean every little hole. I took my time and 2 cans of carb cleaner. Installed the carbs and the thing fired right off. Man does it sound nice! I bought it just to sell. I am going to have a real hard time parting with it. Overall the bike is very nice and clean. Thanks again. I really appreciate the response!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dustyp &raquo;</TD></TR><TR><TD CLASS="quote">Thanks project_mercy for the reply. I tore the carbs off and spent another 2 hours cleaning them. Very carefully removing every single piece of build up. </TD></TR></TABLE>

Rock on! I'm glad it was something as cheap and simple as a carb cleaning. When I 'clean a carb" I actually strip the carb body down to nothing and soak it. The can stuff is just sorta fickle.

Good job on the fix, and ride safe.