Two headers hot, two not

keval · Posted: Sun Aug 31, 2008 11:22 pm Post subject: Two headers hot, two not

Greetings.
Any idea why the inside two header pipes on my CB750 are hot and the outside ones only warm during warm up? The bike doesn't sound as if it's missing any cylinders - is this normal?
Thanks

05c50 · Posted: Mon Sep 01, 2008 6:50 am Post subject:

If the bike is running right all the pipes should be about the same temp. Cylinders 1 and 4 (outside) run off the same coil. Could be a problem with that coil, points (if you have them),wiring. Or it could be fuel related,plugged jets...or it could be a bzillion other things. Need a little more info to really track it down.

.......Paul

redstedman · Posted: Mon Sep 01, 2008 8:45 am Post subject:

I'm going to guess coil. Swap them and see If it goes to 2 & 3. Inspect the coil as they get old and crack and won't work. Cheap and easy fix if thats what it is.

keval · Posted: Mon Sep 01, 2008 9:08 am Post subject:

Shoulda thought of the coils, but I thought they went 1-3 and 2-4. Old age'll do that to you.
I'll give it a try and check back in later.
Thanks,
Kevin

redstedman · Posted: Mon Sep 01, 2008 9:26 am Post subject:

1 & 4, 2 & 3. Could be a wire lose on the coil. Probably not a plug wire as 2 clys are not firing. This will come and go eary in the coil falure(when they get hot) and then just flat quit.