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View Full Version : 748. misfire on tickover. advice needed please

zhed44
24-Jan-2006, 22:18
hi -

after riding for about 20 minutes the 748 started to go on and off one cylinder with much popping and banging every time i was stationary at lights etc. it was fine on the move though.

any ideas?
madmav
24-Jan-2006, 22:22
possible TPS

or just leaning off a little too much

or
crank angle sensor

or Air Leak on exhaust

popit in for a set up!

nelly?

bring it on !;)
zhed44
24-Jan-2006, 22:27
Originally posted by madmav
possible TPS

sorry to be thick, but what is TPS?

[i]or just leaning off a little too much

LOL. i wasn't leaning off at all. ;)

seriously though - i did wash the bike the day before, so i'm wondering if it might be water ingress somewhere
deej
24-Jan-2006, 22:28
spark plugs, sound similair to a problem i had when running my 853 in
weeksy2
24-Jan-2006, 22:29
TPS, throttle position sensor.
madmav
24-Jan-2006, 22:29
zhed
Throttle position sensor
but to be fair it could be somthing as simple as the porcelain crcked or even a dirty spark plug! just check the obvious stuff first

mav
rockhopper
24-Jan-2006, 22:30
TPS equals throttle position sensor (about £130 for a new one). It tells the ecu how far open the throttle is.

I would have thought a problem with it would have affected both cylinders though.

An air leak or exhaust leak would be my first guess. Loose or dodgy spark plug perhaps?
madmav
24-Jan-2006, 22:32
Originally posted by zhed44
[quote][i]

seriously though - i did wash the bike the day before, so i'm wondering if it might be water ingress somewhere

sounds mor like the problem
remove the plug caps and blow out with air!
they wont always dry out with heat as the water turns to condensation and causes the plugs to track out!!
JPM
24-Jan-2006, 22:33
Does the rev counter bounce around?
madmav
24-Jan-2006, 22:34
Originally posted by JPM
Does the rev counter bounce around?

Pmsl! we all know you'rs dont pass 4 thousand rpm:lol::lol::lol:
JPM
24-Jan-2006, 22:36
Originally posted by madmav
Originally posted by JPM
Does the rev counter bounce around?

Pmsl! we all know you'rs dont pass 4 thousand rpm:lol::lol::lol:

Now now.... :P
zhed44
24-Jan-2006, 23:03
Originally posted by JPM
Does the rev counter bounce around?

thanks for all the posts chaps.

in answer to the "rev counter" question, yes it does. that's exactly what it was doing, but only when it was on and off the cylinder. up and down by around 500rpm - (can't remember exactly without going out into the frost with my dressing gown on)
JPM
24-Jan-2006, 23:07
Could be as easy as battery terminals then, I'd first try removing terminals and cleaning them up with some sandpaper and refit...
zhed44
24-Jan-2006, 23:09
Originally posted by JPM
Could be as easy as battery terminals then, I'd first try removing terminals and cleaning them up with some sandpaper and refit...

ahh - come to think of it, i did have the battery off a few days beforehand and i also remember that it was a bit sluggish when i started it that evening.

thanks for that - i hope that's all it is! i'll repost and update in the next day or 2 when i've had the chance to clean 'em up

:D