GS850 running poorly - troubleshooting igniter and coils?

[Nessism]

I don't think the manual procedure is foolproof. I'm not an expert on such matters though.

[salty_monk]

It certainly caused a similar problem on my 801000G. Chased it through the carbs for ages before finally trying a Dyna S....

[Boxxiebox@08]

This is a old post but i have the same problem ! Did you ever find out what the problem was ?

[Chuck78]

The original bike owned by GSOH (Alex) who chimed in above in 2013, got sidelined due to him starting a family. I parted out an 850 since then and saved the carbs for him, but he hasn't gotten back to bikes other than refusing me every single time I try to get him to sell me his '79 GS425!
The original bike in question was a GS850 engine in a GS1100G chassis, and what I was suspicious of was the GS1100G carbs with GS850 jets and I believe slide needles, but I was really suspicious of the needle jet size and air jet sizes... Also found a lot of corrosion that had been cleaned off of the needle jets and other areas by previous owner that looked to potentially have altered the size of the air jets and needle jets...

Had a friend's DR-Z400E that I looked at which did very similar.
"Runs great, just needs jetted for the aftermarket pipe and airbox mod" said his friend who sold it to him.
Ran awesome up to half throttle, but no matter what jet size I put in it, which I went the full range of jets available, same problem, above half throttle, it just bogs...
He put that away for the winter, and next summer I revisited it, noted that it was low or out of coolant...
Filled, ran, checked, low...
Drained oil. There's the issue... Tan creamy sludge... Oil and coolant mixing.
Haven't gotten back to that one as I spent my efforts after that to get his WR400R running good. That's an awesome trail bike or dual sport conversion, not too heavy at all considering it's got 2 strokes too many for off-roading in my opinion!