HELP! Break down diagnosis needed....

[Guest]

Over the weekend I took a nice long ride into British Colombia's interior to Kelowna. On my way home everything was running normally. I stopped for gas, and got back on the road. I was running around 80mph when power suddenly cut. No big noise or anything just a sudden loss of power. After getting her to the side of the road, I could start up, but it wouldn't idle. Ideas? Suggestions? Do you fellas think I need to go back into my carbs? The bike has been solid for a year. Lots of riding. I rebuilt the motor. Added pipes, pods, stage 3 carb kit, etc etc etc....

[chuck hahn]

How clean is the inside of the tank...loose crud floating around could have clogged the in tank filter. Does fuel run from the petcock from an aux line so you can gauge the flow?? Take a line into a bottle and use a line to suck on the vacuum port to see how well it flows. Sounds like a delivery issue for sure. Petcock fklter clogged up or petcock diapram went south are two possibilities I would investigate.

[JTGS850GL]

I'm betting electrical because of the sudden loss in power. Have you determined if all the cylinders are firing and if not which ones? Have you checked for spark on all cylinders?

[chuck hahn]

well he say it would start back up but not idle.....so I wasnt thinking electrical.

[chuck hahn]

pipe, stage 3 carb kit etc etc etc.......... Dont think it was running lean and burnt a valve or holed a piston maybe????????

[JTGS850GL]

well he say it would start back up but not idle.....so I wasnt thinking electrical.

Just thinking he may have melted a coil, connector or lost part of the igniter. It would allow the engine to start but it would not idle well or have much power. Sure hope you're not right about the melted valve or holed piston.

[azr]

Well if the engine isn't/wasn't making any strange noises that would sort of rule out any major engine issues, and if he's been riding the bike for a full year with no issues I'm guessing he got everything right with the carbs long ago. Sudden engine failure but it starts up but won't idle....first things that come to mind for me is a fuel issue. Either out of fuel or your petcock bit the dust. If it were electrical you wouldn't think it would start easily, but it doesn't rule that out. You have some good questions to answer already.

[Sandy]

Over the weekend I took a nice long ride into British Colombia's interior to Kelowna. On my way home everything was running normally. I stopped for gas, and got back on the road. I was running around 80mph when power suddenly cut. No big noise or anything just a sudden loss of power. After getting her to the side of the road, I could start up, but it wouldn't idle. Ideas? Suggestions? Do you fellas think I need to go back into my carbs? The bike has been solid for a year. Lots of riding. I rebuilt the motor. Added pipes, pods, stage 3 carb kit, etc etc etc....

Did it stop running as if you turned the key off or was it running just real bad? If it just stopped running as if you turned the key off it could be a bad ignitor, maybe a heat problem, let it cool and see if it comes back to life or I'd suspect something in the fuse block, remove it from the frame, pull off the back cover and see that one of the wires hasn't come off or shorted to another one. Not the first time this would have happened on an old GS. Maybe a wire worn and shorted to the frame, just move the harness slightly and test again. Could also be an internally open circuit in your battery but if it will turn over that's not likely. All quick easy things to check and rule out.

If it just started running bad maybe you got a tank of crappy gas or you dropped a coil. If the bike has cooled down a bit, start it and see if all 4 pipes heat up. If either 1 - 4 or 2 - 3 don't heat up then you've got either a bad coil or wiring to that coil or a bad ignition pickup. Where are you? Maybe someone from GSResources is nearby.

[chuck hahn]

Coils usually either work fully or quit fully in my experiences..

[60ratrod]

i'm about 45 minutes south of BTreadz. I would help, but I am busy in the yard with my neighbors this week trying to cut down on a rat issue, rewiring a car dolly I just got and putting tires on it, and then I go on leave next Tuesday to Colorado, but i'll be back on the 6th. after that if you still need a hand, shoot me a pm

[60ratrod]

Coils usually either work fully or quit fully in my experiences..

one of my dyna 3 ohms crapped out on only one side. I verified this on both the gs650g and the kz1000 with the same pair of coils. new coils and the kz fires on all 4 now.

[chuck hahn]

Seeing that a GS coil is one winding that fires two wires at the same time and the ignition system uses a waste spark during the exhaust stroke...it aint gonna happen. The coil works or not. Never had a Dyna coil so I cant speak to thier construction...but a GS coil is just that..1 COIL. when its gone two wires go dead.

[Chopperjake]

Bad gas or gas flow issue seems reasonable.

I had a KZ1000 cut out on me like that - turns out the coil was fine but the WIRE was bad and it would only let spark through intermittently. Son-of-a-buck rode home through nebraska on 3 cylinders....

Do you have a timing light? They also make a funny looking spark plug wire with a small light inside that you plug one end into the wire and the other end attaches to the top of your spark plug and then if your electrical system is firing, you can "see" the spark because the light will light up. Costs about $7 at harbor freight.

That will tell you if you are getting spark or not.

Another reasonable diagnostic approach was stated above - let it run for a bit and see if all 4 pipes are hot or not. If one isn't, then it's most likely getting no gas or getting no spark. (I say likely although other catastrophic issues are possible but less common.)

Just my $0.02...

[Chopperjake]

this thing.

[alke46]

I had a similar situation with mine a few years ago and it turned out to be plug wires and caps. Trimmed a little off each wire and installed new caps and viola!

Hope this helps. Reading your post brought back memories of mine doing the same thing. Would start and run fine but you just never knew when it was going to die. Good luck.


Larry