R1250GS exhaust single "pop" on acceleration: any ideas?
Hi again to the Forum: I'm on my fourth GS bike, having taken delivery of an R1250GS in HP trim about six weeks ago, but I had been out of the GS world for about 4 years (focusing on my BMW S1000RR, road racing and general hooliganism). I am loving the new R1250GS, but am mystified by a strange "pop" that happens upon certain kinds of hard acceleration, such as starting from a traffic light, exiting a turn, etc. I have noticed it in several gears, always at low rpm (around 4000 or so). It consists of a single "pop", never more than one, and there isn't any feeling to it, other than the noise. No hesitation or surge, just the pop.
A friend has the same model, and his pops, too.
Searching for this, someone posted about it in a UK GS forum, and it quickly became about the quick shifter's ignition pause mechanism, but this pop happens way before the shift. There sometimes is a "pop" when you shift (just like there is on the RR, it's quite a satisfying "bang" on that one with race exhaust!), but this one is far softer, and again, not even close to when you would shift.
Some say it's the Shift Cam, but from what I've read and seen, that shift happens higher up the rev range...? OR, could it be a load/throttle position reaction to anticipate harder acceleration by the Shift Cam mechanism? Maybe the map senses that you want to accelerate quicker than normal and gives you the higher range sooner than normal?
Any insight on this would be appreciated. Just curious. Not worried, as the other R1250GS does it, too...
(Wanted to post a pic, but since I've never posted - long time lurker - it wouldn't let me)