I have a '77 Suzuki GS750. Was running ok. removed airfilter assembly and it wouldn't start, turns over, but only an occasional backfire. returned airfilter to original, ensured pcv hose and vacuum hose to fuel petcock . Air flow screws for air fuel ratio are all set at 1 and 1/4 turn. Spark on all cylinders and have fuel flow. I suspect points and condensors as one set of points looks burned and very uneven contacts. Am I on the right track? Hekp, suggestions?

SOURCE: 95 xv750 Virago fuel leak

Probabilly a stuk carburettor float or needle.
Try to solve this problem to gently tap on the carburettor bodies. If this doesn't help you have to clean out the carburettors, and/or replace the float neeldes

SOURCE: Bought a 2000 yamaha yzf600r

You can fail emissions on a bike in arizona ? Wow i thought california was bad....anyhoo let's get to your concerns....All those srews should be very close to the same setting....rule of thumb is start at 1and1/2 turns out on each screw, almost any gasoline engine will run at these setting then you can fine tune from there.....no wonder you had bad idling problems...Good luck to you friend....Tim

SOURCE: Fuel Air mixture screw

2 and a half make sure the bike's running when u do it the revs should sit between 1 and 3/ 2 2half

SOURCE: 1989 Zuma, just rebuilt carb to OEM specs, turned

answered

SOURCE: 2003 ttr 125 it will only run when the choke out.

download the repair manual here
http://www.torrentreactor.to/search/haynes+yamaha+ttr+125+repair+manual