Major uneven temps on headers of the 1200.

[John Schmidt]

I have one of those fancy temp doodads where you just aim it and it reads the temp. Just for kicks, I started the 1200 and after a warm up period I started to probe the headers up near the head with the light and was quite surprised at the differences in temps shown. The left side has the biggest disparity....well over 200 degrees. I failed to write down which one was which, but one read around 530 deg. and the other in high 200's to the low 300's. The right side shows a difference as well but not as great, and don't match or come close to what the left side reads. When I rebuilt the carbs I reset the slow jets to the same number of turns out and followed with a carb sync once installed and running. All four cylinders run a tad rich so now I'm wondering if I should just start over by resetting the slows and then see if adjusting them while watching the temp on my "stun gun" (grandson's description) to see if I can bring them closer together. Once done with that, do another sync. The bike runs strong, I'm just bugged by the wide temp variance. If I have time in the next day or so, I'll take a run up to the gas station and back, fill it up and give it a chance to warm up good without just sitting in the garage with a fan in front. Then do the adjustment and monitoring as described, or should I leave it alone?!

I've never checked the Valk's header temps, maybe I'm barking at shadows.

[sinner]

Got similar problem on my Valk.
Interested to see where this goes.

Sinner

[Pete]

Couple of things. Done this to several bikes and I see some variation, but not as much as you are seeing.
Also run it down the road and check it as soon as you stop to see if the variation is just at idle.
It it is just at idle, adjust the idle mixture, if not re-sync.

Chrome or Black pipes? Chrome seems to be harder to get consistent readings because of reflections and requires more accurate pointing.

I use the temp sensor for a lot things and it is very helpful, as in-expensive as they are everyone should have one in the tool box.

[Glaserbeam]

I just had my carbs professionally cleaned (cylinder 1 was getting NO gas at idle - PO had let the bike sit for years) then the idle-drop mixture adjustment.  Started it up and let it idle for a couple minutes and did the point-and-click digital thermometer at the header pipes.  Temps were:  cylinders 1 & 4:  80 degrees.  cylinders 2, 3, 5:  120 degrees.  cylinder 6:  140 degrees.
What the heck is going on?

[Pete]

I just had my carbs professionally cleaned (cylinder 1 was getting NO gas at idle - PO had let the bike sit for years) then the idle-drop mixture adjustment.  Started it up and let it idle for a couple minutes and did the point-and-click digital thermometer at the header pipes.  Temps were:  cylinders 1 & 4:  80 degrees.  cylinders 2, 3, 5:  120 degrees.  cylinder 6:  140 degrees.
What the heck is going on?

Dis-assemble and clean or chemical clean?
Seems 1 & 4 not getting as much gas at idle.
Open idle mixture screw on 1 & 4 to see if it helps. Also check carb sync.

If they were chemical cleaned 1 & 4 jets may not be clean.

[Glaserbeam]

They were removed and disassembled.  Probes and chemicals through every passageway.  I will try syncing next.