K100RS lighting prob

[delawaredrew]

Hi,
My 91 K100RS has developed an odd lighting problem. At around 4000rpm the entire lighting system begins to flash intermittently, getting worse as I rev past that point. I've had a large part of the sys apart and the relay seems fine, no bad plugs or bare wires evident, and no loose bulbs that I can find. I've begun to suspect it's the relay that shuts the elecs down when the starter switch is pushed. Or the bulb check module, though I don't really know what that does, other than alert you of a bad bulb. It is difficult to reproduce in the garage as I don't like to rev it that far up on the stand for long.
Any ideas?
Drew

[JimVonBaden]

Sounds like it might be a short, probably a ground short. The K100 tends to hit a harmonic vibration around 4K rpm, and that might be why that RPM is where you see the problem strongest.

I would verify all the plugs are clean and in good contact.

The K bikes plug into the Speedo head tends to corrode, so you might try pulling it and cleaning it.

Jim

[drew]

Thanks for the tip, I don't remember checking that speedo plug and it isn't too bad to get to it. It's been almost a year now, but I try to put dielectric on all of them whenever I'm in there. So you think that a ground on any one of the bulbs would cause the whole system to flicker? It does make sense. My diagnostic efforts consisted largely of pulling and twisting on plugs, wires, assemblies, etc...I'll keep you posted.
Drew