Hi . Do you have a source for blank nipples ? I think threading my own is the best option . I think that Talon may make 3.5 but at £1.99 each not practical .
Hi . Thanks for all the input on my Alpina project , it’s appreciated . Just got a manual from Bultaco UK ( in motion ) and I’m very impressed with the crankshaft seal arrangement and wondered if the mains could be changed from the outside , using a blind hole bearing puller .
Theres a sheet of mesh or perforated steel plate about 1.5mm thick with a hole for the steel tube. The mesh rests on the flats in the casing, then a flat piece of filter foam, then another piece of mesh to contain the foam, then a washer, a light coil spring and washer that all fits over the steel tube.
The airbox cover/lid also has a hole and there is a large headed screw that screws into the steel tube. It holds the cover on and compresses the spring. The length of the tube limits how far the screw can compress the spring.
As for the bearing ventilation, the crank seal holders rest against the bearing outers and the seals themselves are very close to the bearing
