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Old 09-01-2012, 09:06 PM   #3079
Gnarly Adventurer
Joined: Mar 2012
Location: Central Oregon
Oddometer: 270
OK, I have some performance related questions on my 2002 R1150GS. It has 42k miles and the valves were adjusted and TB sync done at 38k miles, along with an oil change. I put new Autolite 3923 plugs (.035 gap) in 1k miles ago.

1) It's hard starting when cold. It takes at least two 4 second cranks to get started, and sometimes three or four attempts. Once warm, it fires right up. What might be the cause of this?

2) After a cold start, I usually let it warm up to one, sometimes two bars. Invariably, the first time I accelerate on to the road, it stumbles and lags for a second, then "catches" and off we go. It does not do this when warm. Ideas on this? Is it related to #1?

3) I have the typical low RPM surge. I've played around with different configurations, including factory CCP, Steptoe jumper, no CCP, connected O2 sensor and disconnected O2 sensor. Right now, I'm running no CCP and the O2 sensor is disconnected, but it doesn't seem to help. I reset the Motronic by pulling the fuse for 5+ minutes, between each change. After I put the 3923 plugs in, it seemed to help some.

Other than these things, it runs great. Mileage, on E10, is between 36 and 41 MPG. Often, I'm fairly aggressive with the throttle, but It's better on the highway (as I would expect) I haven't been able to correlate a mileage difference with the various CCP/O2 combinations I've tried. Overall, the mileage seems a bit on the low side.

Lastly, if I roll off the throttle quickly, it decelerates hard. I believe this is caused by "overrun fuel cutoff." Can this be improved?

I'd love to fix the surging and increase the mileage, too. I have an Ice Air on order - will it help with any of the above issues?
- Eric
2002 BMW R1150GS
EKinOR is offline