B spec carbs

[mattiec321]

Hi there chaps

Can anybody tell me the difference between the A and B spec carbs?

Would the serial numbers on the carb bodies still start 01AB?

Cheers all

[Davez29]

The only difference I know is the jet size, which is 106, the carb trumpets are all short and the carb rubbers have 53bhp washers in them. In fact quite a lot of the parts are different in number at least, looking in the parts book. I don't know what's different in the carb bodies themselves. The B carbs only came on the R/R2 as standard. 01AB yes.

Reviewing this post I see my podgy finger poked the wrong key. Main jets are 105 not 106, sorry.

[mattiec321]

Thanks for that, for some reason I thought they has adjustable needles

[Hrcnc29]

B specs have different diaphragms diaphragm springs emulation tubes are different mixture screws are different
But the main body is identical

[dunkenb]

I alawys thought (probably wrongly) that the later carbs had a spec to similar to the earlier carbs with a dynojet kit fitted which was why the dynojet kit wasnt available for the later ones??