SWM's and earlier Aprilia's had the PHBH 26 FS carb that had a petrol screw, later Aprilia's have the PHBH26 FS which appears to have an air screw ? Are they any better, or just different ?
The one I'm thinking of using has a small brass connection which I think was a vacum to remove any build up from the crank case, but didnt work and was usually blanked off. Can anyone confirm ?
Thanks
Ross