stalls when hot

[jasper]

It sounds like the heat could be causing expansion somewhere, and that cooling down let's it relax to normal. The fact that it starts up and idles again after cooling reinforces that idea. That is suitably vague, but maybe someone else can pick up that line of thought.

That being said, I haven't the foggiest idea of where that would most likely be happening, but possibly the head/valves. You've already changed the coils. Have you managed to check the voltages once things get hot and the bike starts to stumble/before it dies? Could this be an overheating RR situation?

Hi Derrick -

I'm currently thinking a vacuum leak is opening up when the bike gets hot but your Reg/Rec theory is plausible also. I haven't yet measured the stator output despite a number of suggestions to do so.That's just one more thing I want to try this weekend, lot's of good words written. I have noticed that the R/R actually stays cool to the touch which is counter to my expectations. There's a test procedure in the manual for the R/R too....gotta do that.

I was hoping also to come by and borrow your carb synch tool, perhaps even today? It would be nice to troubleshoot with the knowledge that the carbs are in synch.

My wife and kids are heading out of town sunday/monday and I intend to spend every moment oof that time getting a bike that I can rid etogether.

I have to admit I've also made arrangements to go look at a BMW R100GS for sale. The riding season is running out on me. It's a high mile bike though, and the last thing I need is another trouble bike.

Any chance I can come by to pick up that carb synch tool?

Thanks

[Dave8338]

Have you checked the compression?

[BigD_83]

any progress?

Jasper,

Have you made any ,more progress with the GS now that you're riding your BMW? Oops, did I just out you on the forum?

[jasper]

Hey Derrick.

Success for real this time.

Turns out one of the leads from my 1,4 coil was flaky. It ran ok cold, the impedances were spot on, but when it got hot the #1 lead just failed.

I deduced this by riding until the bike stalled, then pulling each lead in turn and inserting the wire from my circuit tester into the end cap. The banana clip fits perfect right.

Then by holding the end of the wire neat the head, I could observe nice big beautiful sparks when I ran the motor...all except for #1 which was weak.

IN the meantime I replaced the reg/rec - because I was clearly overcharging.

Rode the bike to work today and it's beautiful. Nicer than the Beemer in some respects.

As far as outing goes......no shame in a 1990 BMW K75S and we are allowed more than one bike anyway right?

Thanks again everybody for your help.

[azr]

Nice endings are always the best. Fantastic to hear she's up and running, now go and ride the @#$!!* out of her.