IanC
Guest
Currently in Chile, and my 1200GSA has started misbehaving this morning after over 22,000 trouble-free miles on this trip.
Runs fine up to about 60% throttle, then sounds like it's running on one cylinder. Doesn't appear to be engine-speed or load related, just throttle position, although this varies slightly from perhaps 55% to 70%.
Weird thing is I dropped it in some gravel yesterday, and caught the LH throttle body with my boot and pulled it out of the rubber intake manifold (only at the cylinder side, not airbox). I didn't notice at first and actually fired the bike up, but something was very obviously wrong! Thankfully I managed to get it back in with a little spit, and it seemed to be running fine afterwards, for the rest of the day, 4.5 hours. Problem only manifested this morning - I had thought it might be altitude of 15,000ft, -3C this morning, or dodgy petrol, but I've now descended to half that and put some good 97-octane gas in (after nearly empty) but still the same. Besides it has been fine at similar altitudes so far, if down about 1/3 on power. It did take a little starting this morning, but this was probably the temp/altitude.
The throtle position sensor and injector leads are obviously OK as the bike won't run without them (or one cylinder only), so the only one that could have been damaged is the one on top, and I'm not sure what this is? I had thought that maybe the intake manifold was not sealing properly and sucking in air, but it looks fine and I would have expected there to be problems at LOW throttle rather than high if this was the problem, due to more vacuum.
Or maybe it's just a coincidence - does this sound like dodgy spark plugs? After all the bike seemed to be running OK for a while.
The bike is rideable, but I'm about 900 miles from nearest BMW dealer in Santiago (who has a not-good reputation anyway), so would like to try and sort the problem myself.
Runs fine up to about 60% throttle, then sounds like it's running on one cylinder. Doesn't appear to be engine-speed or load related, just throttle position, although this varies slightly from perhaps 55% to 70%.
Weird thing is I dropped it in some gravel yesterday, and caught the LH throttle body with my boot and pulled it out of the rubber intake manifold (only at the cylinder side, not airbox). I didn't notice at first and actually fired the bike up, but something was very obviously wrong! Thankfully I managed to get it back in with a little spit, and it seemed to be running fine afterwards, for the rest of the day, 4.5 hours. Problem only manifested this morning - I had thought it might be altitude of 15,000ft, -3C this morning, or dodgy petrol, but I've now descended to half that and put some good 97-octane gas in (after nearly empty) but still the same. Besides it has been fine at similar altitudes so far, if down about 1/3 on power. It did take a little starting this morning, but this was probably the temp/altitude.
The throtle position sensor and injector leads are obviously OK as the bike won't run without them (or one cylinder only), so the only one that could have been damaged is the one on top, and I'm not sure what this is? I had thought that maybe the intake manifold was not sealing properly and sucking in air, but it looks fine and I would have expected there to be problems at LOW throttle rather than high if this was the problem, due to more vacuum.
Or maybe it's just a coincidence - does this sound like dodgy spark plugs? After all the bike seemed to be running OK for a while.
The bike is rideable, but I'm about 900 miles from nearest BMW dealer in Santiago (who has a not-good reputation anyway), so would like to try and sort the problem myself.
