SSMOKINNNNNNNN'

Hoping someone can enlighten me. I finally got my bike to the point I was going to take it for the inaugural ride.....idling nice, rebuilt the front calipers/master cylinder, headlight...to cut to the chase. Had it idling there for about 5 mins. and smoke started coming out from I guessed the cylinder head cover....not exactly sure where it's coming from. Pulled the gas tank and the top bars are smokin' hot. I don't see any leaks around the cylinder head cover. Coils maybe? Any ideas are appreciated.

Thanks!

Did you try touching the coils? If they're getting hot enough to heat up the top frame rails that much they'd definitely feel hot to the touch. If the coils aren't superheated you'd almost have to be running real lean to get that hot, have you checked the plugs? If you're real lean they'll be white...

I didn't check how hot the coils were. I had just pulled the plugs and they were black (too rich) so I did back out the air screws about a 1/4 turn. I will get her going again and see if I can do some additional fine tuning and check the coil temp. Seemed AWFULLY hot though.

What would make the coils heat up like that?

check your grounds

Check grounds, yes.
Also check voltage while the bike is idling. The voltage should never go over like 15.5V at any time.

Don't let the bike idle for very long intervals. Are you sure it was only 5 minutes, cause these old bikes can overheat if the idle circuit has a lean condition, and they are left to heat up without getting some movement.

GL!

OK...seems I'm a dork. I had the air screws turned out one whole extra turn. The coils don't seem overly hot, I think they are ok but I will check the voltage. I did the coil mod a while back and everything checked out ok at the time.

The crankcase breather is smoking pretty good though. I've only had this bike running (and I say running as in idling sitting still) a few times for a few minutes each. Prior to that it was sitting in a barn for few years.

I think I'm closing in on this thing...hehe....famous last words.

If the bike has been sitting along time you are likely to smell all kinds of things as the motor warms up. Make sure you clean the tank real good so you dont suck up all the crud into the carbs.

Yep....the tank was pretty rusted up. I cleaned it out really good shook the hell out of it with some closed link chain and about 100 1/4" nuts , then used "prep and etch" phosphoric acid to clean up the last of the rust. All and all, came out ok. I also added in-line filters to the fuel lines.

So there's a chance this stuff is just left over sludge and such that has accumulated in the cylinders and crank case? When I got it, the bike was bone dry, no oil, no brake fluid, and the carbs were pretty grimy.

I'm sure these are all newbie questions, this is the first bike I've worked on....hell, I've haven't done much with any vehicle.

Thanks for all the great info guys!

Would also sniff-test crankcase oil to check for possible fuel intrusion into the crankcase (which may result from clogged carb overflow circuit).

Good Fortune!

If just idling and checking things out with engine running.... Throw a cooling fan (home circulating fan) aimed at the engine... this is a must!

Remember, these old KZ's are air cooled... of which you have none just sitting there so it will get severely hot...

OMR

If it's lean and running hot, you will see it in your pipes close to the head. They will start to blue. As far as the plugs, just choking the bike and warming it up without driving it can dirty up the plugs. Need to get out there and ride it to clear up those plugs.