Starts, runs, then won't start

[tkent02]

When it doesnt start check for spark and fuel in the bowls.

Fuel makes sense but why would there be spark in the bowls?

[chef1366]

Fuel makes sense but why would there be spark in the bowls?

C'mon guy!

[Colorado85gs550]

just a couple of Colorado guys cranking your balls chef...........we have to deal with so many Californians around here that giving a Bakersfield guy a bad time is GREAT

[Big T]

When it doesnt start check for spark and fuel in the bowls.

Chef,

That's an ignition problem for an entirely different forum.

[chef1366]

Chef,

That's an ignition problem for an entirely different forum.

So what???
Diagnostics is diagnostics
Or are you giving me crap too?

[joeninpo]

I think that they're all telling you that too many Californians spark up way too many different types of bowls :-) Just a guess......

I took the motorcycle for a nice ride this afternoon and tinkered a bit with the throttle adjustmet until I got it at just around 1000 rpm. The bike ran great and scooter around the block beautifully. I brought it home, stopped it, and it started right back up. I rode it around for about 30 minutes more, brought it home, and when I tried to start it up again, the battery was deal. Totally seperated issue, but definitely highlights the fun and enjoyment of driving a 30 year old bike!

After I fix this problem, I'll update to let you all know whether the throttle adjustment worked for sure. More to follow....

[chef1366]

We do have Humboldt Co.

[Colorado85gs550]

well I'll say this....after I rebuilt my petcock last night it ran great but this morning, however, it ran for exactly 10 minutes again and shut off! I did notice this time the rectifier was so hot it burned my finger when I touched it.....after only 10 minutes of run time.

I'll be changing that for sure now...........something you may check into as well, being that it was intermittent for me and it was the EXACT set of issues you are having.........

[joeninpo]

Hmmmmm....I wonder if that could be causing my battery problem as well. I thought my charging system was good until today, but I'm not so sure anymore. I'm going to do the below recommended tests on it later and see what happens.

[SqDancerLynn1]

The only way is to check the charging system with a volt meter
The rectifier / reg will get pretty warm. If yours turns out to be bad ? get a Honda Reg from Dundege?
It will cause battery problems and could be the source of your intermittent problem too !!

[Colorado85gs550]

I don't think mine is a voltage problem at all, I tested again today with fuel cap off and petcock in PRI position.....it ran for exactly 10 minutes again then died. It wouldn't restart until I sprayed starter fluid into the carbs, then it fired up and ran until it burned off the starter fluid.

This suggests that voltage is fine and that we are suffering from a fuel supply problem. But why only when it's warm? What are we missing?

[KEITH KRAUSE]

As derwood said earlier, sounds a lot like poor gas tank venting. Runs fine at cold start up then the problem shows itself as things warm up. No re-start while warm unless you let things cool (unless you remove the "vacuum" by popping the cap). My first experience with this type of problem was with a lawnmower.
Not saying positively that it is but it's so easy to clean out the gas cap vent (basic maintenance anyway) that it's worth a try. If not done in a long time or used on a bike that sat a lot, the venting gets clogged up with "varnish".

[Colorado85gs550]

I tested again today with fuel cap off and petcock in PRI position.....

Wouldn't this show that it isn't a blocked vent? The cap was OFF!

[joeninpo]

Grrrrrrrrrrr......

My problems keep piling up. I have to fix my electrical problem first so that I can diagnose my fuel problem. I love driving a 30 year old bike! I cleaned all of the connections tonight. They obviously hadn't been cleaned in forever. I'm charging the battery tonight to see if that fixed things and then I'll reattack the fuel problem. I have to say, though, that it's running better already with just raising the idle speed up to around 1000 rpm. More to follow.............

[Big T]

Joe,

While you're in there, add a ground from the R/R directly to the negative post of the battery


It's been know to boost the charging rate and it only takes a few minutes