Exhaust Pipe Cold - KZ650 - and rattling.

If it is only 1 pipe that is cold on start up but warms up when actually riding, I would suspect a clogged pilot circuit.
If it never warms up I would think in has to do with wiring.

bluej58 wrote: Which pipes are not getting hot?
The rattling noise may be from a loose or bad exhaust ring, when the bike is cold grab the exhaust pipes up by the head and try to move them sideways , if you find any movement try to tighten down the flange , if that dosn't help replace the rings

Well I changed the spark plugs today.

When I took out the old one cylinder #10) there was oil on it, but not the others.

Started up that bike and smoke came out of the left hand exhaust (bike still has the original exhaust). When I roll the throttle even MORE smoke comes out.

So what might this be?

Valve guide seals.
Steve

1+ Steve, as i reply in 650Dude other post, renew the valve stem seals first.

www.kzrider.com/forum/2-engine/609433-19...uild-hope-not#792394

SWest wrote: Valve guide seals.
Steve

Im indebted to you guys. thanks so much!

Scirocco wrote: 1+ Steve, as i reply in 650Dude other post, renew the valve stem seals first.

www.kzrider.com/forum/2-engine/609433-19...uild-hope-not#792394

Many thanks to you as well.