Boxerworks.com

My right hand carb rattles, at large throttle openings above 4000 rpm it can be quite unnerving. I have a 1979 R80/7 with a sebenrock 1000 cc conversion which runs on 32mm flat tops. It never rattled before the conversion. I have put in brand new slides but the rattle persists . I am trying to ignore it but really I want it to go away. I have considered a new carb but can't find one, I bought a second hand one but it looked worse than the one I had, but who knows how many miles its done, my bike has been around the clock by the way. Why don't the Chinese make cheap copies like they do for everything else.

Flat tops don't have a guide sleeve like the dome top Bings, instead the slide has to be a reasonably good fit in it's bore but not too tight otherwise it wouldn't fall under it's own weight and there are no springs on a flat top to help it. I've never had that problem with my flat tops or heard anyone else have that problem before now with Bings but you do hear of slide rattles on some other carbs. It has to be related to vacuum pulses but why only on a 1000 ccc I don't know.

If you are going to look at replacement carbs there is no reason why you couldn't use dome to Bings.