Overheating???

OK, I'm nearly done resurecting my 1983 KZ1100. I have driven it nearly every day for the past two weeks although usually only for 10-15 minutes. This past weekend I took my longest drive. Not going anywhere in particular...just having fun and practicing my driving skills (just completed the BRC two weeks ago:)). About 30 minutes into the drive I found a deserted parking lot and practiced my low speed manuvers for about 30 minutes.

Now, here's my problem. After driving at low speeds for 30 minutes the bike became quite hot. My seat actually became so hot that I stopped the bike, turned it off, and checked under the seat to make sure that everything was OK . Looked OK but was quite hot under there. Thinking I should get back out on the highway to cool it off, I closed the seat and tried to start the bike. No go. Turns out the main fuse was out. I pulled out the old fuse which was hot to the touch and replaced it with a spare. Now I try to start bike and it BARELY turns over. I think the battery was fine (headlight was bright) but engine turned really hard. I let it cool five more minutes and finally it did turn over enough to start up. Drove home and was carefull not to kill it on the way. At home checked the battery and voltage was good. After letting it cool for a couple of hours turns over and started normally again.

Is it normal for a bike to overheat while at low speeds? How do you avoid this if you get stuck in traffic? Also it was only about 65 degrees outside. What will be be like during the summer.

Note that I had previously dissembled, cleaned, and balanced the carbs. Spark plugs look OK. Number 3 has just a bit of white on the tip of the plug so I opened the pilot jet a little. Others are dark brown so I left them alone.

Sorry for the long post.

Post edited by: NormZ, at: 2005/10/24 09:29

Post edited by: NormZ, at: 2005/10/31 15:27

It's going to get hot after 30 minutes of low speed (parking lot) driving. That bike is air cooled and needs lot's of airflow to cool it, at low speed like you are describing, it's not getting the airflow to cool it. The reason it would not start is because it was too hot, and the metal had expanded taking up the normal operating clearances, causing metal to metal contact.

If you want to practice low speed driving with the bike, then I'd shut it off and let it cool down for 1/2 hour or so after 10-15 minutes of riding.

you might want to check the timing also, too much adv, or even a retarded condition can cause overheating

I've found I occasionally have the same problem after highway driving as well. After a long drive, if I turn off the engine then try to start it back up, the starter barely turns over. More often than not I blow the master fuse trying to re-start. After 15-30 minutes, all is fine.

Would an aftermarket oil cooler help? Or is this a sign that something else is wrong.

As I said before, fuel mixture seems OK. Also checked valve clearance and that is OK. Timing advanceor is free, although I do not have a timing light to verify (electronic ignition). A light will probably be my next tool purchase. I also have not checked voltage to the coils. I plan on making that check at my next opportunity.

Post edited by: NormZ, at: 2005/10/31 15:25

An oil cooler would help some, but you still need the airflow to keep it cool. Slow speed riding for a half hour will build up an awful lot of heat. Feel how hot you clutch cover gets after riding for a while at highway speeds, and that's with good airflow.