GS850GN - ignition fault

[Anonymous]

HI! I've recently had a few problems with my 1979 GS850GN.

Engine starts up fine and runs well for 30 sec. or more,. perhaps several minutes, and then it dies...

If I try to start again, it won't fire the first time, but 2. time ok. It dies again and if I push the start-button shortly, and push it again to start it runs again but dies sooner or later...

If I'm lucky if I can drive a mile or so, and it dies out, but a short push on the start-button while I'm driving and it goes again!

It has later-fitted transistor-ignition, and it has allways been driving very well and reliable.

I think it might be some kind of ignition fault, but which?

Any idea of what the cause might be?

[arveejay]

The exact same thing happened to me after a coil swap with the wrong coils.

[Guy]

Yep, coils and amplifier might be mismatched. Have you recently converted from points/changed coils?

[Anonymous]

It has been driving with the transitor ignition now for 5-6 years with no problems untill now, and I haven't changed anything that might have caused the trouble - could it be the AMU or perhaps the ignition switch?

[Guy]

You could try bypassing the ignition switch by running a temporary wire from the battery (+) to the coils. (Connect it to the orange/white connector at the coils). If the bike runs ok like this, the problem is likely to be with the ignition/kill switch or associated wiring.
Held og lykke!

[Anonymous]

Thanks a lot for your answers - I'll give it a try with bypassing the ignition switch - I'll come back when I've tried! Regards Ib

[feelergaugephil]

GS850

OK, everyone looked at electrical, but I had a simular problem a few years back............
It was the fuel filter (attached screen) in the tank! check that before you start ripping coils out.

[bwringer]

It sure sounds like fuel starvation to me.

[earlfor]

I think you have a fuel feed problem. The next time you start up the bike, let it run until it dies as usual. Then turn the ignition off and remove the drain plugs on each carb float bowl. I suspect you will find there is no fuel in the bowls. If there is and a normal fuel amount is in each bowl (aprox 1 1/2 to 2 ounces, then it is not a fuel problem.

The first thing you must do is determine whether it is a fuel problem or an electrical problem.

Earl

[Anonymous]

Hi Earl!

That's what I thought the first time, but I have checked the carburettors and the fuel level and amount is ok.

I'm sure it is an iginition problem.

When I'm driving the road, and the problem occur, the engine suddenly dies and is braking the bike down, and I just have to activate or rather touch the starter button very shortly, and the engine spins instantly and the bike is running again - often followed by a "big bang" caused by the fuel absorbed in the exhaust system...

It is as if the electrical impulse from the starter does something to the electrical circuit/electronics to make it work again...

I haven't had the time to bypass the ignition switch yet, but I'll let you all know when I have tried it.

Regards Ib

[focus frenzy]

check/clean the contacts in the engine kill switch on the right handle bar switch pod, (above the starter button) a dirty contact in that switch can cause symptoms like that, also check the plug for the harness for the right handle bar.

[Anonymous]

Hi Leon,

I think you've got a point there - I'll try it - thanks!

Regards Ib