Britbike forum

Classic British SparesKlempf British PartsBaxter CycleBritBike Sponsor SteadfastCyclesThe Bonneville ShopLowbrow CustomsSRM EngineeringGirling Classic MotorcycleLucas Classic MotorcycleHepolite PistonsIndustrial tec supply



BLACK FRIDAY MEMBERSHIP OFFER 2021



50 % DISCOUNT ON ALL OPTIONS!!!


Upgrade your membership: Premium Membership Gold Membership Life Membership

50 % DISCOUNT ON ALL OPTIONS!!!



New Sponsor post
The BLACK FRIDAY SALE is here!
by The Bonneville Shop - 11/23/21 5:29 pm
New FAQ post
How to find my own threads?
by reverb - 11/20/21 3:55 pm
Manuals on DVD - Buy 4 for 3
All 4 DVD Manual
Member Spotlight
umjwh
umjwh
Lowell, Ind
Posts: 53
Joined: February 2006
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Top Posters(30 Days)
Rohan 74
NickL 73
Top Likes Received (30 Days)
Newest Members
Gus_Carrero, mogmike, Julian1966, BSACliff, Bezza Frank
11,920 Registered Users
Who's Online Now
3 members (Tridentman, Doug P, Bigtwin), 20 guests, and 16 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
#859021 09/21/21 1:37 pm
Joined: Apr 2003
Posts: 51
R
Britbike forum member
OP Offline
Britbike forum member
R
Joined: Apr 2003
Posts: 51
Quick question please?
Can B31 cylinders be used on a B33 bottom end? Any problems _if_ they can physically be mounted on the cases?
Thanks, Ron

BSA on eBay
Joined: Apr 2003
Posts: 51
R
Britbike forum member
OP Offline
Britbike forum member
R
Joined: Apr 2003
Posts: 51
Quick question please?
Can B31 cylinders be used on a B33 bottom end? Any problems _if_ they can physically be mounted on the cases?

Or; Put another way. Can a B31 cylinder be bored out and used on B33 cases???
Thanks, Ron

Joined: Feb 2014
Posts: 940
Likes: 140
Britbike forum member
Offline
Britbike forum member
Joined: Feb 2014
Posts: 940
Likes: 140
Hi Ron
Yes the crankcases are the same so the B31 cylinder will fit
But you cannot bore the B31 cylinder to the 85mm size of a B33
Some people bore the B31 cylinder to 76mm and use a Triumph piston to get near 400cc
Not exactly straight forward as I believe the crank needs re balancing to avoid bad vibration ??

John

Joined: Aug 2001
Posts: 138
Likes: 2
P
Britbike forum member
Offline
Britbike forum member
P
Joined: Aug 2001
Posts: 138
Likes: 2
crank does not need to be balanced, also you can take out to 79mm b44 piston


A7, A10, B33, B31, A65, C15, T100
Bantam
1 member likes this: SouthendMike

Moderated by  Allan G, Jon W. Whitley 

Link Copied to Clipboard
Job CycleBritish Cycle SupplyMorries PlaceKlempf British PartsPodtronicVintage MagazineBSA Unit SinglesBritBike SponsorBritish Tools & FastenersBritBike SponsorBritBike Sponsor






© 1996-2021 britbike.com
Powered by UBB.threads™ PHP Forum Software 7.7.5