Joined Nov 2001
17K Posts | 773+
Ely, England
i have had to renew my throttle plate on the keihin. if any of you have a used keihin off an early model you must watch for this! they crack around a circular dished area and the cost is £90 to renew....
the way to tell is i believe (not 100% sure on this!) that the underside distance from the 'O' ring to the bottom of the slide is about 3mm.
on later carbs it's up nearer 6-8mm. this gives it strength all the way around the slide and it won't break.
you can hear the slide plate simply by putting your hand over the end of your pipe at tickover. the back pressure will rattle the throttle plate!
it's this continouos rattling that fatigues them and in the end they crack. however, there is one cure you can try and that is simply to renew the rubber 'O' ring that fits the plate. this would have to be ordered seperately anyway but with a new one you will have a firmer fit and less 'rattle'. this should give you possibly an infinite lifespan....
regards
Taffy
the way to tell is i believe (not 100% sure on this!) that the underside distance from the 'O' ring to the bottom of the slide is about 3mm.
on later carbs it's up nearer 6-8mm. this gives it strength all the way around the slide and it won't break.
you can hear the slide plate simply by putting your hand over the end of your pipe at tickover. the back pressure will rattle the throttle plate!
it's this continouos rattling that fatigues them and in the end they crack. however, there is one cure you can try and that is simply to renew the rubber 'O' ring that fits the plate. this would have to be ordered seperately anyway but with a new one you will have a firmer fit and less 'rattle'. this should give you possibly an infinite lifespan....
regards
Taffy
