Bike will not start when hot

[syren]

Hi Everyone,

I have an 83 VT500c and here is a quick description of my problem, I'm hoping that you guys can give me some things to troubleshoot, if you need more info please let me know.

The bike will not start after it has been running for more than 5-10 minutes. I have to wait 30-40 minutes for it to cool down, then it will start. It has a new battery, I've replaced the coils will used coils that were taken off of a working bike and still have the same outcome. When I try to start it when it's hot, it tries to turn over and doesn't. I do get a few backfires if I try for to start it for too long.

Not sure if this something electrical or if it's something with the gas being too hot, I've heard of that before, not sure how to troubleshoot. Any help would be appreciated. Thanks!

[oconeedan]

So the engine is turning over, but won't start, when it's hot?

[CBH]

The starter brushes are probably worn out.

[oconeedan]

Originally Posted by CBH

The starter brushes are probably worn out.

That was my first thought, but then he said it backfires when he tries to start it when hot. That would indicate something other than the starter.

[syren]

Hi guys,

The engine is turning but wont start. It doesnt alway backfire but does if i try to start it for long enough.

[callmeal]

How about valve adjustment?
Sometimes they act like that when the valves are too tight.

[CBH]

Originally Posted by syren

Hi Everyone,

When I try to start it when it's hot, it tries to turn over and doesn't.

Originally Posted by syren

Hi guys,

The engine is turning but wont start.

We seem to be getting two different stories here!

[oconeedan]

I would lean toward a carb problem.

[Ralph Ky]

I think i understand that it is cranking but does not start but will backfire if it is cranked for more than should start the bike.

I have an 85 vt500 that does the same thing sometimes .
It will cold start just fine with choke .runs great but if you shut it off it will start back if if you start it within a couple minutes ...
But if you let it sit for 5 - 10 minutes it will crank backfire crank backfire.....
If you let it sit for 20 to 30 minutes it will start right up and run like a top....

[syren]

Originally Posted by Ralph Ky

I think i understand that it is cranking but does not start but will backfire if it is cranked for more than should start the bike.

That's a good description Ralph, I was confusing cranking and turning over.

What should I be checking next?