I've been trying to find out what the thread forms were for the A 65 inner, outer and chain case screws. I should know really I worked at BSA Smallheath from 1964 to 1971. I understood the early A65s (and A50s) were 1/4 BSF but have heard a suggestion that the inner timing cover screws might have been cycle threads. I know they all changed to 1/4" UNC in 1969 (I think). Does anybody know the definitive truth on this. I have looked through a number of books I have on the model and can find nothing.
:) :) :)
This is not specific to this post but might be of interest.
A couple of times in the recent past I have bought 1/4 bolts/screws of various thread and they were very slack. On checking properly I have found them to be threaded on 6mm shank with the correct thread (1/4) cut on them. They hold ok in the casings but I would be very wary of using them wheres erious tightness is required. Obviously insufficient thread depth.
Mike 8) 8) 8) 8)
Might be worth contacting these people and asking:
https://www.ebay.co.uk/itm/373503295694?hash=item56f68800ce:g:PEAAAOSwjqVZHK47
Same old same old again.
BSF or BSC 55 degrees instead of 60..
:) :) :)
Trouble is Chaz, we are talking to a generation that if it aint M6/M8/M10 etc they havn't got clue.
Mike 8) 8) 8) 8)
yes, but its also a case of that will do.
its as close as we can get at the right price, M5 for 2BA, M6 for 1/4 Whit, BSF for BSC and these supplied by reputable !! British bike spares people.
the original cross head cap screws are good looking but cost too produce and most engineering firms dont have the kit to make them now.
I had a Laverda 750, basically a big BSA 650, to do a genuine restoration on it requires bolts with Laverda cast on the head, tooling no longer available.
the thing with thread angles is the correct screw fits the flank angles wheras the different angles mean a smaller contact area.
Hi,
Early years were CEI, changed to UNC around 1968/9 onwards.
Best wishes...