Topic: another carburator posting...

[El Guapo]

I read the FAQ's and just want to get your folk's opinion.

I'm riding a '74 350F1, which has been in storage the last two years.  The carbs are freshly rebuilt, jetted and bench synched.  then on-the-bike synched but i didn't like the results so i started again

Second synching and First Conunudrom:  I backed the mixture screws out a tad beyond the 1 1/2 turns because it was running rich, backed the synching screws out to begin again and then the bike started revving at 4000 with choke @ 3/4 open, 1200 with choke fully open.  what would cause that??  Since then the bike starts and revs immediately to 4000-5000.  the idle stop screw is backed out completely.  Mixture seems not to affect this at all I can only control this by OPENING the choke until the revs decrease.  Might i have installed the wrong size jet?

Second Conundrum: carbs 1-3 register and adjust fairly well but #4 will not register.  adjusting the synch screw in to get #4 to register kills the bike suddenly and without warning. would a leaking intake boot cause this? what other causes might there be?  Where would I find another intake boot, or will I have to do w/ silicone?

thanks,

[jay72chevy1]

yes a cut intake boot will cause excessive over rev. It will suck in air forcing it to breath. I had that happen to me on a 2 stroke dirt bike i had an intake boot ripped and boy did it rev and run like crap rev and then run lke crap etc.

[El Guapo]

hey, thanks for the tip.  I only get about once every three weeks to actually work on the bike (why it was in storage for three years).  I'll have to check this weekend and have another go. 

I'm starting to panic since the riding season's almost over...