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Discussion Starter · #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
 

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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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I had that issue when I first got my Cm400 running, one carb needle was worn badly, the other not at all. Worn needle = more gas at idle = hot right cylinder, lukewarm left in my case.

But there are many more causes, check out the carb rebuild threads.
worn carb needles should not have any impact on idling mixture...if they do then your carbs have several other issues as well
 

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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
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)
 

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Discussion Starter · #5 ·
It's noticeably hotter both at idle and after driving but I am expecting a reg/rec in the mail any day now so maybe that will help. It's a '71 350 I just picked up about a month ago. The PO still had the stock charging system on it
 

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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.
 

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Was referring to what outobie said
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
 

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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
Thank you ! That makes so much sense... other than why its not 360 degrees between each firing... but I'll leave that up to the Honda engineer.

Sent from my SM-G930V using Tapatalk
 

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Discussion Starter · #13 ·
Thanks for all the replies btw this forum really is a great resource. I work with a couple Harley guys and it's always doom and gloom with them whenever I mention the slightest problem with my bike ��
 

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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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