Bike Won't Idle - Running out of Ideas

[St. Hubbins]

After doing some work to my GS425 bike over the last month, I can't seem to get it to idle once it's warmed up. It holds an idle well cold, but inevitably once I go for a five minute warm-up drive, when I come to a stop it will gradually bog down and die trying to idle (I've been aiming for an idle in the 1-1.3k RPM range).

Aside from the idle issue, the bike seems to run fairly well on the road. My thinking is that it has been running rich, based on the running better cold and easy cold starts, and the exhaust smell seeming to me a bit gas heavy. At this point I'm running out of ideas. Anyone have any thoughts on what I should look at next?


Work I have done in the last month:
New carb boot o-rings
New carb boots
Carb rebuild (new o-rings, dip, carb clean all jet/carb passages and clear with comp. air)
Float height adjustment (I've tried various heights with no change, as measured from surface without gasket in place)
Airbox rubber gaskets are in good shape and look to be sealing well
Air filter was recently washed and oiled (I then washed it again to get basically all oil out, thinking it was contributing to running rich)
Carb sync (with home manometer setup I feel good about, but mulling over just getting a real device to make sure)
Mixture screws adjusted by highest RPM method, somewhere around 2 turns out now

Other notes:
Plugs don't look particularly sooty or dark.
Float needles and seats appear to be sealing well, also tried cleaning up today with valve compound and q-tip method, blowing on fuel line I don't get any blow-by when they are seated
Static timing is right on
Compression 130 psi left and right
Valves recently adjusted and in spec

I've been running some tests with a temporary water bottle fuel tank so I can get access to carb sync screw. Idle issue has occurred with this test tank as well as real tank, so I don't think petcock/fuel flow is part of problem.

Voltage at coils is 11.4 and 12.4 (I think this is cold reading, though I could check hot, may do the coil relay mod anyway and I picked up a 5-pin Bosch)
Primary coil resistance is 4.9 ohms on both, about 5.4 ohms each when hot
Secondary coil resistance is 12k on both, with plug boots removed, and between 12k and 13k ohms hot

Any help or suggestions are appreciated.

[TxGSrider]

So have you tried turning the idle mixture screws in about 1/4 turn?

[St. Hubbins]

Yes, bike still dies trying to idle.

[St. Hubbins]

I think I've sorted it out. I rechecked the carb sync and it was a little bit off. 3/8 of a turn clockwise on the syand it's now holding an idle. In the meantime, I also went ahead and did the coil relay mod and replaced the spark plug boots.

[60ratrod]

with one coil getting 11.4 and the other getting 12.4 tells me that there was an electrical issue. did the relay mod fix it and get them both the same volts?

[St. Hubbins]

Yes, relay mod fixed it, they're both getting same voltage now.