Won't start when hot. mechanical or gremlins?

[DrDoot]

This past week, the bike will not start when hot. I can get up in the morning, ride to where I need to go, leave a few hours later(starts fine each way), but if I stop anywhere, and then try to restart the bike 5 minutes later, it's a no go(was starting up if I turned off and then turned right back on, but not if it was a few minutes in between). Can't push start it either. I have to wait a couple of hours for it to cool down, and then it'll start. It got worse today, with the bike stalling at low RPM after a short ride, and then not starting even if attempting it right away.

This has all come with the hotter weather. And if the bike is left out in a sunny parking lot, it barely starts with the choke all the way in(normal). This is all new to me. Any help would be appreciated, as somebody told me that there might be gremlins in my bike. Now I don't know what gremlins are, but I do know what I don't want to pay an exterminator to get rid of them. Any help or advice would be appreciated.

[chef1366]

Is the starter turning?

[DrDoot]

Yes, starter turns, and I might get one little grumble, but it won't fire up(when hot).

[courier11sec]

I'm new to bikes, but if it were a car doing that I'd look at the coil. You can be pretty sure it's an ignition problem.

[chef1366]

I hear the igniter can be heat sensitive when failing.

[DrDoot]

A faulty coil would be effected by heat alone? The bike will have a harder time starting when it's hot(in the afternoon) after just sitting all day.

[DrDoot]

I've never changed the spark plugs on the bike, are they a possibility?

[quakeholio]

I don't think that they are the culprit, but I change mine every year.

[DrDoot]

Between the ignitor and the ignition coils, which should I change first?

[relic-rider]

This could be several things. Don't jump to the conclusion that it is electrical. Test it first. Pull the plugs when it fails to start. Good spark? or not. If there is spark, most likely it is carb related. A rich condition in the carbs worsens after riding and getting hot, while a lean condition is worse when cold and gets better when hot. You need to check the float height and the needles and seats for leakage. Could also be a vapor lock sort of problem. Check the fuel line and its routing. Also check the carb vent lines for being plugged up. Look at your plugs. I bet they are black and sooty.

Dan

[Tervo]

Also, if valve clearances are too small, it could lead to starting problems when hot. Kawasakis are very famous doing that...

[DrDoot]

9 months later....

Finally got the bike running yesterday afternoon. I can't say exactly what the problem was, but I can say that it was in the ignition system somewhere. After replacing just about everything individually, and frying two CDI igniter boxes, I decided I would figure out how to fit a Dyna ignition on the bike.

After ordering a Dyna S and finding the appropriate mechanical advancer from an '80 GS something or other, I thought I was good to go. As soon as I pulled off the ignition pickup cover, I knew I was in trouble because the plate of the Dyna is as big as the entire ignition pickup cover. Also, apparently Suzuki changed from a 3-point mounting system to a 2-point mounting system in '82. I then had to drill holes in the Dyna plate to match up to the factory holes, find some longer mounting screws at the hardware store, make some spacers out of a piece of narrow pipe to fit behind the plate and hold it off of the mechanical advancer, and I wasn't done yet. I then had to make more spacers from the same pipe and find longer bolts for the ignition pickup cover to fit over the now much longer mechanical advance/ignition pickup. To seal the 1/2 to 3/4 inch gap created by the spacers, I used weather stripping and a mess of RTV.

FYI for those who run into the same problem. Bike runs fine now.

[chef1366]

Thanks for sharing your fix.