installing 165 cylinders

seattle##gs · May 13, 2021

I just finished installing a set of A65 cylinders and ran into an odd problem. The studs in the case didn't exactly lign up with the cylinders, either in front or in the rear. It took several good whacks with an orange hammer to get it to slide over the studs. Is there two different A65 cylinders just slightly off from each other? The motor turns over freely.

mean gene · May 13, 2021

Are both case halves matching? Have limited experience with A65 but have rebuild a couple with no problems. Anxious to hear what the experts say

EstuaryBoy · May 14, 2021

According to Mr Wilson's BSA book the stud's diameter was changed in 1970 (from 5/16 to 3/8)
Might that account for it? (Assuming it's a 'bitsa')

seattle##gs · May 14, 2021

That's probably it. This motor comes from a Rickman dirt bike. It worked in this form so I assume it will work again. There was plenty of room for the studs but they weren't in the exact spot they should be. Close but needed persuasion to mate barrels to case.

seattle##gs · May 14, 2021

Talked to Jrc..they have no idea but claim there is no difference.

slimslowslider · May 27, 2021

FWIW

The 1969 parts manual:
- mentions 5/16"x1-7/16" studs, 2 off in EN15 and 6 off in EN14B material.

The 1970 parts manual:
- mentions 5/16"x1-7/16" studs, 2 off in EN15 and 6 off in EN14B material.
- 2 studs are drawn with a "dowel" type untreaded middle section.

The 1972 parts manual:
- mentions 3/8" x 1-11/16" studs, all 8 off in EN16 material.
- 2 studs are drawn with a "dowel" type untreaded middle section.

seattle##gs · May 28, 2021

They fit but no drop-on. On turning it over several times it has free motion. Will move on to next problem.

installing 165 cylinders

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