Need Help with tuning Webers

[Gun Doc]

priobe

I don't have much experience with Webers, but I have read about them and have plenty of experience with Harleys and other bikes with similar problems.

When "reading" plugs, you should always start with a fresh, properly gapped set...For each run. Webers run on the idle circuit up to around 3000rmp, so you should make a run from a start up to 3000rpm, then like ERA626 said; clutch in, engine off, coast to a stop and pull the plugs. They should be light tan. Black (sooty) indicates an over rich condition (too much fuel).

If the 3000rpm run checks good, but you still foul plugs, you should do another run (fresh plugs) up to 5000rpm, or so. Same thing start from a standing start then put in clutch and shut off the engine. Problems here could be with your mains, as the idle circuit does nothing after about 3000rpm.

Jay is right on when he states that you should be at 3/4 turn on the idle mixture. You should never have to go more than 3/4 of a turn to get it right. If you have to go past that, you probably need to go up in idle jet size. Your problem sounds more like your jets may be too large, or the mixture screw is too far out.

Like I said, I am no expert but the above are pretty basic tuning tips when it comes to Webers.

Gun Doc