weird surging thing haunted bike

[minkyhead]

done 8000miles gear box seal went so replaced no problem
mechanic said he had had problems with surging as the thottle bodies had to be removed to do the job ...but it had settled down quote meaning he didnt know why it seemed ok when i took it but
three days later ...
now on occasions you start the bike hand off the throttle and the revs surge bettween one and three thousand revs not slowly.. like a bloody see saw just jike you were blipping it
switch the bike off and let it re set it stops happens every now and then
ive searched the forum but cant find anyone else this has happened to
in between the bike runs fine

anyone any ideas please ???

 

[JimVonBaden]

Sounds like a vacuum leak to me.

Jim

 

[Aitch42]

Hi I had a similar problem and so did a mate of mine. It turned out to be an electrical problem. There appears to be a sensor somewhere that monitors the vacuum or something and it can come loose when people fiddle with the engine. My mate took his back and the garage sorted it - I just pushed every connector I could find and not had a problem since.

Sorry it is not very technical but I would try the re-seating thing before you panic.

Aitch

 

[Swooper]

It happened to a mate of mine. It just happened to be a loose battery terminal.

 

[minkyhead]

surged to death

well thres bad news wierd surging started again when on a instructors course in bedford almost put me into traffic on a dual carriagway bike just started reving to 5 thousand and back uncontrolably ..the examiner thought i had gone stupid
switched it off and starter motor appeared to have seized
started after 5 mins limped back to test centre wouldnt start again the
managed to start it said left it running for 5 mins whilst talking to my freind he then said f/??? H!!! LOOK AT YOUR BIKE
it was dusk and the exhaust headers were glowing yellow with heat for 8" either side you could see the glow refleting off the tarmack
yiu could smell the burning swithched it off rang bmw assist told them not to send man in a car because it was insafe to ride ..so they sent a man in a car
fortunatly he was a bike man he said they will glow a bit if yiu leave it running so he started it after two mins he said ...oh dear i see what you mean and called out a recovery van
went back to southport superbikes they have replaced parts governing throttle and fuelling but worryinhly have not identified the fault to a specific item .cant knock the respose from bmw or s superbikes but wonder what would happen if i was in the middle of norway on me hols s

the morol of the story is any surging symptoms take it in right away cos it bloody scary when it kicks off