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One side running wayyy hotter

6K views 13 replies 6 participants last post by  Yendor 
#1 ·
Has anyone had this issue before with one side of the bike running a lot hotter than the other side? I'm assuming it's my mixture, I think I've probably got one side running rich and the other running lean but I just figured I'd double check with the forum before I start farting around with the carbs again because the bike really seems to be running well that's just something I noticed. Maybe I just need to run a hotter plug on one side due to uneven wear? Thanks for the input
 
#2 ·
What bike?

Are you checking the header temp at idle? After a run at highway speeds?

If at idle more likely due to carbs not sync'd so you're pretty much idling on one cylinder. Really bad mixture adjustment is also possible.

If after a run you likely have plugged/restricted fuel passages or jets in one carb or possibly float level out of spec. You don't want 2 carbs with different jets in each. You also don't want different plugs in each cylinder (and it wouldn't fix this problem anyway).

Possibly cable/linkage not opening butterflies evenly off idle.
 
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#3 ·
worn carb needles should not have any impact on idling mixture...if they do then your carbs have several other issues as well
 
#4 ·
JT is correct but I would emphasize that if you can touch the header without burning your hand then that cylinder isn't firing consistently. there are a multitude of possible causes ranging from carbs, to ignition to compression to the health of your battery and charging system. a very common issue is that one cylinder won't fire at idle and then begins firing as revs pick up (which in turn can be caused by carb synch or health of charging/battery)
 
#10 · (Edited)
You are either charging or not
put a meter on the battery
run at idle and then at 3500 rpm

report voltage back here

also test both with lights on and then with them off

if you are not charging at idle it can drop a cylinder then pick it back up when you start spinning the motor higher

keep in mind the ignition timing of this motor...
first left fires then 180 degrees later right fires then 540 degrees later left fires again .

the left coil always has 3x longer to charge than the right coil

you havent mentioned which which headder is the cool one.

if the right one is the cool one then start trouble shooting electronics.

if left is cool one start with fuel and carb synch
 
#9 ·
Yeah, the hot one may be the one that's running correctly. I'd say you probably have one cylinder running wayyy colder than the other, or not running at all. I know you said it's running well, but have you looked at the plugs to compare their appearance? That can tell you something, too. Also, if you're still running points, make sure both are opening/closing correctly, are gapped right, and nothing's shorting out inside the points compartment.
 
#14 ·
The COILS have an UNEVEN Charging Cycle.

You can look and see which one opens 1st on the cycle and that one "COULD" get more fully charged with the points being closed for a longer duration.

The second one "MIGHT" get charged as the RPM's come up and the Voltage in the Charging system rises.
These bikes don't reach full charging output until approx. 3500 RPM.
 
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