KZ650 Warning: Exhaust Smoke and Valves *UPDATE*

Im posting this for the benefit of anyone who might encounter a similar problem.

I usually keep ALL of my bikes on their centerstand.

For the past few weeks Ive had my KZ650 on a non-stock, lower side stand.

As a result OIL built up in cylinder 1 and when I started the bike yesterday, some came out of the exhaust on the left/cylinder 1 side. I put the bike on the centerstand overnight and started it up again. VOILA, no smoke. Seems like all the oil that leaked into CYL #1 burned out. I ALMOST took the top off the engine to replace the valve seals. Im glad I didnt.

Bike is back to normal.

Maybe I'm just a noob, but if oil leaks into the cylinder while the bike is on the side stand, that sounds like leaky valves to me?

What colour was the smoke?

It not smoking when after sitting on the center stand is because there isn't oil pooled up on cyl #1. It probably has a slight leak and sitting overnight with a puddle of oil on the seal gave it enough time to leak some past. I need to change my valve seals as well.

gavroyer wrote: Maybe I'm just a noob, but if oil leaks into the cylinder while the bike is on the side stand, that sounds like leaky valves to me?

Not necessarily. If oil pools above the #1 valve guides after sitting for hours on the side stand, and if the valve guides have a bit of a leak, the oil will pass the guides and end up on top of the valves, or if either valve is open while the engine is shut off the oil will run inside the cylinder. Even if the intake valve happens to be closed when the bike is sitting, if oil accumulates on top of the valve the oil will be drawn into the cylinder as soon as the valve opens when the engine is started. Ed

650ed wrote:

gavroyer wrote: Maybe I'm just a noob, but if oil leaks into the cylinder while the bike is on the side stand, that sounds like leaky valves to me?

Not necessarily. If oil pools above the #1 valve guides after sitting for hours on the side stand, and if the valve guides have a bit of a leak, the oil will pass the guides and end up on top of the valves, or if either valve is open while the engine is shut off the oil will run inside the cylinder. Even if the intake valve happens to be closed when the bike is sitting, if oil accumulates on top of the valve the oil will be drawn into the cylinder as soon as the valve opens when the engine is started. Ed

Now I think its the carbs. Bike ran well enough today, but I took out the plug in cylinder #1 and is was black as night, not oil fouled but black and sooty. Other plugs were fine.

Bad spark plug cap?
Steve

SWest wrote: Bad spark plug cap?
Steve

No idea. Its def getting spark. Shocked the heck out of me when I pulled it off with the bike running. Doing a compression test tomorrow. Im betting somehow its the carbs, although I DID see an oily plug the other day, and smoke, all of which has stopped.

So odd. The bike starts on the first kick, but I feel distinct power loss at 4-5k rpms.

Have you performed normal routine maintenance such as checking/adjusting valves, adjusting carbs, replacing points, etc., etc. ? Ed

nevermind