sudden bang and lurch - twin cam

[WindyChuffer]

I like to preload the gearlever before shifting to take any slack out of the system. With it preloaded momentarily dip the throttle and the gear drops in as the transmission unloads. But the GS shifter seem very sensitive, so preloading can accidentally whack the gear through anyway - not good.
I tend avoid preloading the lever but help it with the clutch. Matched revs give a smooth shift.

Preloading the lever does seem to work for clutchless downshifts on the GS. On a closed throttle gently press the pedal until you feel the selector then momentarily (and minutely) blip the throttle. The transmission unloads and the gear drops in. I personally prefer the clutch miss-match revs blip method as its less fussy or maybe Im just better at it.

WTF are you on about? In English pls....

 

[Mark Hooton]

improper gear selection 100%

+1

Happened to me last year - all down to improper non-positive gear selection

 

[Mark Hooton]

WTF are you on about? In English pls....

+1 lol

 

[Shep]

I don't think the OP says weather he's accelerating, braking or what, it would be nice to know what the bike was doing before it lurched, i've never had a BMW lurch up a gear? (I did have a Royal enfield that would do that)

 

[Engineer]

odd one this. out for a ride with a pal I had a bang and a luch forward exactly as if said pal had run into my rear wheel but he was a good 20 yards behind me. I didnt stop immediately but when I did I couldnt find anything wrong. Rode on for another 30 miles or so with no issues at all. Neither of us saw anything in the road. Bike is a 2012 with jut 2k on the clock. No bevel box play.

Any ideas? Best I can think of is something to do with boots and gear change. The lurch was reall quite big.

If the bike is running fine and nothing appears broken then forget it, chill and carry on if there is a 'real' problem I am sure it will rear it's head again and then you can worry!