That happened to me, BMW said it was from twisting the throttle before or when starting. I now first wait for the bike to idle before playing the throttle, never had problems since
I would like to make an offer on this 1977 Yamaha xs 750. Bike runs well. The seat however needs to be finished. I have no idea what this is worth. Surfing the net prices range from R13k to R40k.
Beautiful 650 on gumtree going for a song:
https://www.google.com/search?q=bmw+650+ceres&rlz=1C1AVFC_enZA767ZA767&source=lnms&tbm=isch&sa=X&ved=2ahUKEwj4ofyB1-j3AhXFiVwKHfJQBsYQ_AUoAXoECAEQAw&biw=1366&bih=600&dpr=1#imgrc=tWpzLfggOAcHYM
My speedo sometimes does the same. Did some net searching. It can be caused by movement of the accelerator when ignition is on. Something to do with calibration. I now don't have my hand on the accelerator when starting and I haven't had the problem since.
I looking for any vendors/bike shops in the pretoria area that are open tomorow. I am looking at buying soft lugage, maybe a spare helmet and accesories for F800gs.Thanking you in advance