I had a very similar problem with the 851, mainly backfiring. I was then informed by a knowlegable chap that when i stall the bike, as am proned to do when cold, I should turn the key to off before restarting the bike. This resets the computer. Since this bit of advice I have not had a splutter since. :sing:

Sorry Shazaam,but it`s defo a mechanical tacho on these 851/888s,look for poor or loose connection Andy,and try crunchies proceedure and see if that works

Rode the bike again today and it also backfires on overrun occasionally which makes me think its a fualling problem.

Is anything adjustable on the fuel system on these bikes?

Hi andya, i am experiencing the exact same problem with my 91 reg 851, nearly had me off twice last week on a run out, have tried to monitor when it happens the most, cold/hot/wet/dry weather conditions or when the bike is cold or hot etc, seems very intermittent and thats the thing that catches you out. Went all the way to Assen and back without a glitch and then happened twice on a local run? the only thing that i can locate is it seems only happen on wide throttle openings in 4/5/6th gears if anything. My bike does backfire at times but i thought it was probally due to it running race pipes/air box mods etc...
Going to monitor this thread with interest..:roll:

Well apart from what I suggested previously, have you changed the fuel filter. Another thing I have done is fuel with a higher octain fuel. When I first got the bike about 7 years ago I was fueling with normal petrol because some not-so-wise-man said it would be fine. Since filling up with a higher octain fuel and making sure I switch off completly when stalling I have not had a single back fire or stutter. :sing: