Cylinder "heat"

[Anonymous]

My bike, a 79 GS750L, seems to run "hotter" in cylinders 1-2-4 then in #3. I just got this cylinder running and wonder what would cause this. ALL of the carbs are spotless(I have now cleaned and recleaned them 3 times in three days!). I now have this bike running(though I haven't been on the road yet, it is 10:45pm here and my header is without baffle) and don't want to mess anything new up!

[focus frenzy]

have you synchronized the carburetors yet??
synchronization balances all four carburetors so they open and flow the same allowing all four cylinders to work evenly and the engine to run smoother.
if number three carburetor is not opening up as much as the other three cylinders, it will not be working as hard as the other three and that pipe will be cooler.

[Anonymous]

Just out of curiosity, can the float level affect this as well?

[SqDancerLynn1]

79?? you have the slide carbs?? The petcock vacuum line goes to the #3 carb, check it for leaks, Check the compression on #3 and valve adjustment

[saaz]

Float levels, carb synch, air and pilot screw adjustments can all lead the these problems. A basic check of the mechanical condition (valve clearance and cylinder pressure) is a basic starting point.

[moto_dan]

If your petcock vacuum line comes from #3 pull your vacuum line off at the intake and notice if even a drop of fuel runs out. If so then you have a hole in the diaphram of your petcock causing #3 to draw raw fuel through the intake causing an extreme rich condition which would explain the cooler cylinder. Easy check and one that is often overlooked.