Bike dies after 3 hours, overheating?

[Guest]

I rebuilt the carbs for the second time two days ago. Soaked overnight in lacquer thinner. Installed an inline fuel filter and a new oiled-foam air filter. Bike ran much better.

Rode for 3 hours yesterday then the engine cut out. I was cussing up a storm. My friend picked me up, we went back an hour or two later and it fired right up, ran smooth, and we rode it home.

This morning, I checked the mixture for highest idle, and headed out again. Right at three hours into the ride (in the desert) the engine cut out again. It doesn't want to run.

I poured what water I had on the head, the left side boiled instantly, the right side didn't. So I turned the idle air screw in 1/2 turn on #1 and #2.

It won't start. I'm currently on the side of the desert highway waiting for it to cool off, hoping it will run fine again just like it did last night.

The pipes aren't blueing, so I don't think it's running so lean that it would cause itself to overheat at 70mph.

Bad coils?

I'm gonna take a nap and check back in 30.

Thanks
-Matt

[tom203]

When it cut out, was it quick (i.e like electrical) or prolonged (i.e fuel starvation) ?
Did you start today with full tank and this stuff happened as you got down into 1/4 tank area- still have petcock filter? have you looked at it to make sure it's not gummed up in lower area?

[Agemax]

take the gas cap off see if it starts then breather hole in cap may be blocked, or partially blocked

[lemonshindig]

Drilled a new hole in the gas cap this morning, yes I cleaned the fuel petcock, it dies in a fuel starvation way, I can sort of keep it going a little longer by pumping the throttle.

I'm about 3/4 of a tank right now, filled up around 1:00 pst.

[Agemax]

try switching it to PRIme

[chef1366]

Get a Dyna S or replace the points and condensers.

[Flatline_Racing]

Remove the inline filter. They have been known to cause fuel starvation problems.

[kdo58]

I had a similar problen had a large fuel filter it would kink the fuel line when it got hot felt pretty dumb when I did figure that one out.

[tkent02]

Three hours both times..... Isn't that about when it should go on reserve?

[lemonshindig]

Both times were about 20 minutes after filling up.

I have the no-reserve petcock.

Well I made it to Kennewick, which was about another 70 miles, without issue. It is definitely heat-related, sitting in the shade for an hour solved the problem.

My vote is vapor lock. The fuel tees I got from z1 are aluminum, and thus great heat conductors. When I'm riding, fuel flows enough to keep them cool, but once I stop for gas, the fuel in the tees vapor locks, and then I break down half an hour down the road when the bowls run dry. Sitting allows the tees to cool and let fuel flow again.

This is my theory.

[Agemax]

you wont ride half an hour on the gas that is in the bowls. the only way you will get a vapor lock is if the vent tubes are blocked or the gas cap vent is blocked.

[lemonshindig]

you wont ride half an hour on the gas that is in the bowls. the only way you will get a vapor lock is if the vent tubes are blocked or the gas cap vent is blocked.

Well both the gas cap and bowl vents are wide-open. Hmm.

[tkent02]

Re think your theory.

[earlfor]

Both times were about 20 minutes after filling up.

I have the no-reserve petcock.

Well I made it to Kennewick, which was about another 70 miles, without issue. It is definitely heat-related, sitting in the shade for an hour solved the problem.

My vote is vapor lock. The fuel tees I got from z1 are aluminum, and thus great heat conductors. When I'm riding, fuel flows enough to keep them cool, but once I stop for gas, the fuel in the tees vapor locks, and then I break down half an hour down the road when the bowls run dry. Sitting allows the tees to cool and let fuel flow again.

This is my theory.

Those fuel T's don't get hot at all, at least not too hot to hold in a bare hand indefinitely. They ain't the problem. Best guess is a blocked screen on the fuel petcock.

[HammerHead]

Get a Dyna S or replace the points and condensers.

Listen to the Chef Man. Your condensers are bad.