Jockey Journal Forum banner
1 - 8 of 8 Posts

·
Registered
Joined
·
48 Posts
Discussion Starter · #1 ·
I just got hold of a B31 BSA and am going to get stuck into the build in the next few weeks. What I need is a bit of info on the engine build. I am planning building the 350cc motor to start off untill I can get hold of a 500 barrel and piston.

I really need an exploded diagram of the engine as its in bits and I want start putting it back together. If there is any tricks to get a little more power from these engine as well that would be appreciated.

Will put up pics in a new thread once its under way.

Cheers guys
 

·
Registered
Joined
·
48 Posts
Discussion Starter · #4 ·
Thanks for the words of encouragment Haynuzband. Haha.
I have seen one before but cant find it again, will keep searching. I did come across a 500 barrel today and got it for free from a local guy. I will order a new piston and ring set in the next few days.
 

·
Registered
Joined
·
150 Posts
Plenty of info around for these cool old beasts.Keep an eye out for goldstar cams.
They go pretty well as a 350 ,you may poss.encounter some balancing problems dropping on a 500 top end while using 350 flywheels and will need to bore out cases for the spigot.
650 triumph pistons fit into the 350 barrel relatively easily as do the 750 pistons taking capacity to around 440cc.I have a heap of info but have no easy access to a scanner but if you get stuck it can be done.Keep us posted on progress
 

·
Registered
Joined
·
304 Posts
tubby i'm down in Melbourne, i have a '52 B33 and a '51 M21.

heaps of info on the B series singles on the interwebs, Dudley is right with the BritBike forum, lots of relevant info on there under the Goldstar section.

as '59 said try HERE for a download of the Draganfly parts inventory which shows all the factory exploded diagrams.

I believe the 350's had slightly different crank cases and flywheels from the 500's so you'll need to probably open up the top of the cases for a 500cc crank assembly. These bikes are pretty agricultural but can make some good power with only a little bit of work like cams and head work.

PM me for my phone number if you want to have a chat, also Scoresby MC swap is April 1st, Honda Broadford Bike Bonanza is over Easter and the All British Rally is coming up. i'm heading to the Castlemaine area in the next few weeks to buy some M20 and B series parts from an old chap, let me know if you're after anything.

-nick
 
1 - 8 of 8 Posts
Top