Author Topic: BSA B31 / B33 interchangeability  (Read 5252 times)

Offline Snooper

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BSA B31 / B33 interchangeability
« on: June 18, 2013, 12:32:51 AM »
can a B31 Barrel/piston be fitted to an M33/B33?  would i have to change crank/rod ,head/valves ?
Reason i am asking i i cant get hold of a 500 barrel anywhere.
thanks

Offline rogerwilko

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Re: BSA B31 / B33 interchangeability
« Reply #1 on: June 18, 2013, 01:27:37 AM »
You would lose compression using a B31 bore with the B33 head. Hang in there and keep looking. Or get a B31 head and bore the 350 barrel out to 76 mm and use a Triumph T140 piston .