Synchronizing Carbs

[Anonymous]

Not to put too fine a point on it, it's snapping the throttle shut after snapping the throttle open that sucks out the mercury.

Correctomundo - my mistake.

[Anonymous]

If you're really ambitious, I'd do a valve adjustment prior to the carb sync because if you do end up doing a valve adjustment at some point, you'll want to resynch the carbs. I personaly like the dial guages simply because I'm not fond of mercury but if you've got money to spend, there's always the carbtune guages. The dial guages can be easily calibrated by using all four on one carb and adjusting them accordingly.

[Anonymous]

I have a mercury guage, but the book (Haynes) says the two outer cyclinders should be higher, but what should they be set at and how much higher should the out ones be? Does any one know what the Fuel screw should be set at? 1982 GS850L...

[Anonymous]

Bump.

So what is the deal with the different vacuum heights suggested for the 1980-1982 models?

[earlfor]

The Clymer books show setting the outer cylinders (1 & 4) to a slightly higher vacuum level than 2 & 3. A higher vacuum means a higher intake velocity.
(volume remains unchanged) An example of that would be idle. You are increasing vacuum, but the engine is running at the same rpm, so its volume requirement is a constant. Increasing vacuum increases venturi effect and consequently fuel draw. Therefore, increasing vacuum, richens the mixture.
Aluminum conducts heat better than air. The 2 and 3 cylinders are surrounded by aluminum while 1 and 4 are open to air on one side. 2 and 3 will run cooler than 1 and 4. So you would want to set up 1 and 4 a little richer than 2 and 3 to get an even power impulse on all four cylinders.
I have found in practice, that I cannot tell any difference in performance or the color of the plug burn by doing this, so I no longer bother. If you do, the difference to set is 1 cm hg.

Earl

Bump.

So what is the deal with the different vacuum heights suggested for the 1980-1982 models?

[Anonymous]

Thank you Earl.

Kelly