I have a 2001 MXZ 800 with a possible problem. New piston, rings, sleeve, etc. on one cylinder, new rings on the other cylinder. Put twin pipes on and started it for the first time. It was idling at 2000 RPM's for about 10 minutes. The pipe with the rebuilt cylinder was hot, but the other pipe was only warm. Both plugs are good. Is this normal?

The only time I've seen pipes not hot, are when plugs are going
bad. Did you try switching plugs as I know you say they are
ok. With my 800, my EGT's will show 200 degrees colder when
a plug is going bad. It still idles and runs decent, but not full.

I'll try that. Thanks.

You said that you sleeved the one cylinder. Was it originally Nickasil, cause if it was and you sleeved it and the other is still Nickasil then you would have to change the jet in the sleeved one.

If the one side is fresh it will probably run hotter until it breaks in and gets a little clearance.I'd take it easy until things even out.

Try putting it an a test stand and running it fast enough to bring both slides off the idle stops and see if it is still cool, may be as simple as idle stop settings.