YipcanjoDotCom
New member
So, I'm at a bit of a loss here. My '78 R100 has been gone through and gone over for the better part of this year. New wiring, Motogadget brain, new ignition coils, and (of course) new Mikuni VM32 carbs. It's a long story that's probably too sad for a forum like this
Anyhow, I've had help getting my Mikuni carbs dialed in with the right parts and decent settings. Brand-new VM32 carbs left and right. 3.0 slides, 40 pilot jet, 6DH3 jet needle (on the middle clip), and a 159 P-0 needle jet. I'm in the Seattle area, which is part of why those parts/settings were chosen. I had very good support from Bill @ Rocky Point Cycle getting to where I'm at.
All that said, the bike is now starting great, it idles perfectly (~950 rpm or so), and initially runs down the road with no issues. Unfortunately, after about 10 minutes or so -- I guess when fully-warmed -- the bike starts to cough under acceleration. It's similar to how a bike runs when you're running out of gas. At a stoplight (idling) it runs great again. The behavior sounds "starved of fuel" to me, but according to the Mikuni Pocket Tuner guide, it's more representative of a TOO RICH condition. My research also shows that it's likely in the "needle jet" or "jet needle" portion of the carb, if it's actually carb-related at all. I just don't know if I keep throwing parts at it to figure it out, or look elsewhere for the cause.
Thoughts or advice? Should I be looking at timing or valve clearances?
Thank you in advance.
Sincerely,
Stymied in Seattle
Anyhow, I've had help getting my Mikuni carbs dialed in with the right parts and decent settings. Brand-new VM32 carbs left and right. 3.0 slides, 40 pilot jet, 6DH3 jet needle (on the middle clip), and a 159 P-0 needle jet. I'm in the Seattle area, which is part of why those parts/settings were chosen. I had very good support from Bill @ Rocky Point Cycle getting to where I'm at.
All that said, the bike is now starting great, it idles perfectly (~950 rpm or so), and initially runs down the road with no issues. Unfortunately, after about 10 minutes or so -- I guess when fully-warmed -- the bike starts to cough under acceleration. It's similar to how a bike runs when you're running out of gas. At a stoplight (idling) it runs great again. The behavior sounds "starved of fuel" to me, but according to the Mikuni Pocket Tuner guide, it's more representative of a TOO RICH condition. My research also shows that it's likely in the "needle jet" or "jet needle" portion of the carb, if it's actually carb-related at all. I just don't know if I keep throwing parts at it to figure it out, or look elsewhere for the cause.
Thoughts or advice? Should I be looking at timing or valve clearances?
Thank you in advance.
Sincerely,
Stymied in Seattle