Hi,
I have a 1968 T100R and I need half of a case. There seems to be a lot of T100C's but not a lot of R's.
are the cases interchangeable?
Uh-uh ... pre-'69 350/500 crankcase 'halves' might have the same
part numbers but they aren't interchangeable - "the same". Jim is absolutely correct - crankcase 'halves' castings were bolted together, machined and then both 'halves' were stamped (on the lower engine mounting) with the same code, to ensure they were reassembled together after disassembly. That's why you read that replacement crankcases were supplied in "pairs" (of 'halves').
You
might get a 'half' that
appeared to match the one you have, but the pair will require measuring by someone who knows old Triumph twins to ensure main, cam and gearbox bearing housings are true and/or any machining necessary to make 'em so. By the time you've paid for that, you might as well have your original 'matching' crankcase half repaired (as you've asked and been advised already)?
If you're looking for a cheap way of getting a pair of usable crankcases, ... 'fraid there isn't one (otoh, there are several 'cheap' ways of fcuking-up what're currently perfectly good parts). As the saying goes, if you don't have the time and money to do the job correctly now, when are you going to have the time and money to fix a balls-up?
Btw, you do know:-
. pre-'69 and '69-on 350/500 bottom-end parts are completely different and not interchangeable at all;
. apart from 350/500 bore differences, "juggs"
are interchangeable?
Hth.
Regards,