Need Help - Bike dies when warm!!!

[dobie1708]

I'm pretty new to the site and I'm just getting my bike going again. I've been following the advice in Basscliff's site and trying not to make Newbie mistakes, but I'm not the best wrencher in the world.

I have a 79'GS 1000 that was pretty clean when I bought it but didn't run....It has 29 mm smooth bores and a 4 into 1 header, and some kind of period correct electronic up grades.

I just cleaned and sorted the carbs, installed new intake boots and O rings, adjusted the valves (changed 3), and put a new battery in. It ran pretty good right after I put carbs back on, however after putting it all back together after the valve job it dies on me once it warns up.

On the first ride after I put it all back together, it ran pretty good for a mile or two, but got progressively worst until it died and would not start again. I was stranded a few miles away from the house and tried to make a few phone calls...no luck. So I tried to start it up again, but the new battery seems dead. Let it sit for about 30 minutes and tried again...battery seemed weak, but it started up. Got on and headed back to the house, and it ran great for about a mile and died all over again. Again, battery seems dead and would not start.

Finally, my buddy called back and came to get me with the trailer. When he showed up about 30 minute later, the bike would turn over but would not start again.

I know...I ramble, but I need some direction. HELP!!!

[BassCliff]

Hi,

Once in a while I will notice that my carbs will start to slip out of the intake boots and develop air leaks. It's part of my regular maintenance to check the O-clamps and make sure everything is fitted properly.

While you had the carbs apart, did you check what size jets had been installed? Any change to intake or exhaust (pod filters or 4-n-1) require jetting changes to maintain the proper air/fuel mixture.

If you still have the airbox, did you ensure that it is air tight? Did you replace the airbox-to-carb boots?

Have you gone through all of the items on the maintenance lists? Until all of the items have been properly addressed it will be difficult to troubleshoot.


Thank you for your indulgence,

BassCliff

[chef1366]

Bad petcock?
Rusty fuel tank?

[spyug]

I had a Yammie Virago that did this to me. Stranded me 4 or 5 times before we figured it out. I rebuilt the carbs about 20 times it seemed like even pro cleaned twice and it still did it. Finally determined it was a bad coil.

When the bike is cold it started fine but after 10 or 15 minutes, sometimes a bit more it would sputter and die. wouldn't start again until it cooled off. It seems the coil windings were fine when cold but when they warmed up there was likely a break in the winding that opened up when the wire heated and expanded. New coil and it ran fine.

I would check for something like that. Run the bike in the driveway until it dies. Then check for spark. 2 of the leads likely won't have any and that's your problem.

Good luck and let us know if that's it.

spyug.

[tom203]

Bad petcock?
Rusty fuel tank?

Yeah, debris has made it to carbs and plugs things up randomly- I had a Subaru do this, very annoying!

[dobie1708]

Carbs are tight in the intake boots and new O-rings, and the pods are tight. The tank was just cleaned out and flushed...it seems perfect. No changes to the jetting either.

It seems like an electrical issue....as it started and ran fine both times and then got worst as I rode it down the road. It seems like it went to 3 and then 2 cylinders until it died.

I charged up the brand new battety last night and I plan to check if its charging tonight and go from there.

I'm im the middle of going down the maintenance list now...have most of them checked off....also I'll let y'all know what kind of aftermarket ignition is on it.

Thanks for the thoughts and direction....it's been fun getting this old bike back to life. Sometimes I think I should have cut my teeth on someting a bit less complicated though!!!

[dobie1708]

Also, Should I pull out the plugs and check them since it ran so badly???? They may be all gassed up.

[tom203]

Yes, and also check/ run petcock in "Pr" spot to rule out fuel delivery problem. Makes sure tank cap vent is clear.At next episode of suddenly dying, check for fuel in bowls - the "3 to 2 and died stuff" sounds like fuel starvation.

[chef1366]

Also make sure your tank is getting vented. When it stops running take off the fuel cap and see if the tank is pressurized.

[Gorminrider]

...really sounds electrical. a short circuit killing the battery. The nice new battery is recovering when you turn ignition off. but it won't live long at this rate. only going "A mile or two" suggests a bad short circuit...Spyug's post per hot coils is a possibility but there are plenty more on old bikes with old wires ..their dry brittle skins massaged too often....
Sometimes you can see what's wrong if you look hard for it... melted,discoloured wires under the tank (that you had off, right?) look for wires not connected.

Maybe just charging circuit? but you can see if the charging system is working before you go out on a ride...I'm not sure how far a bike will go if the charging system is no good, but more than a mile and much further with the headlight off!! so I favour short circuit by the sound of it.

Whatever,refer to BassCliff's site, electrical troubleshooting, check voltage at battery etc.
Using a simple 12 volt bulb with two leads to make tests can tell you a lot.So can an ammeter, to find where the current is flowing when it shouldn't be.

[dobie1708]

Well I just got home and put the hot battery back in and it just spins over. Nothing.

Here is the crappy part.....the oil is full of gas!!!!! I'm draining it now and plan to refill it, turn it over a few times, and drain it again with a new filter. Sucks!!!

I just ordered a Pingle Petcock and adapter plate....I'm done with Vacume Petcocks.

Looks like I'm on hold as far as chasing down the latest problem. When I get the new Petcock installed and the tank back on I'll hit y'all up.

Thanks