Thumper Club Forum

Technical => Bike Problems/Questions => Topic started by: guest1406 on October 28, 2015, 03:52:00 PM

Title: BSA B40
Post by: guest1406 on October 28, 2015, 03:52:00 PM

Hi all,

Ive still no luck on my little GN.

I have however bought a BSA B40 Distributor engine for near nothing. It is however in parts, but it came with lots of manuals and tools, damn different threads. The head is spotless too, its been at the engineers for dual spark plugs, bigger valves, guides and springs. Cant remember what the valves are from but i'll find out. The bore has just been bored to a +10 too which is promising, also comes with piston and rings too.

I plan to really jazz the engine up, near full rebuild, paint and polish. The "Old Boys" who live near me say they used to polish the inside of the the casings and covers for better oil flow. I do question it but I'm going to do it anyway. Any other neat little old tricks I could do?

So thats the engine, Im after a frame next. Im not too knowledgeable on frames but I know that some models frames are identical, if not very similar and also some Triumph frames are the same so dont mind using a different frame. I know of the TriBSAs etc. I know the B40s weren't, but Id really really like an OIF frame. Plunger too but thats pushing it ha. Anyone know which frames i could use?

Thanks for any help,

Mackenzie

Title: Re: BSA B40
Post by: iansoady on October 28, 2015, 05:10:11 PM

The distributor engine was an early version and not particularly highly regarded although they can be made to go well. I'm always amazed that what started out as an Edward Turner designed 199cc tiddler (the Triumph Terrier) ended up as a firebreathing 500......

WRT frames it will drop into any of the C15 family and you can put heavyweight BSA forks in to make it handle a bit better. Or you could look for a Rickman or similar.

Title: Re: BSA B40
Post by: johnr on October 28, 2015, 07:26:55 PM

yep, if youre on a budget, the c15 frames can be had for reasonable enough money, but girder forks are inexplicably expensive, even indian made replicas of dubious quality are fetching 400 quid plus a set! if you know anyone who could copy them, ive a set you could borrow to copy, otherwise its the autojumbles and ebay and hope you get lucky, but as i say, theyre daft money now.

Title: Re: BSA B40
Post by: iansoady on October 29, 2015, 11:15:25 AM

Apparently some of the Indian made girder forks have cast bridges rather than forged which makes them susceptible to fracture......

Title: Re: BSA B40
Post by: guest1406 on October 29, 2015, 01:30:12 PM

Cheers guys, ill look for a c15 frame. I think ive got the the plans for a front end a few bits for it.

I do however plan to hardtail the frame - not sure how they go down on here!

When I pick the engine up ill post a few pics

Mackenzie

Title: Re: BSA B40
Post by: Oldtimer on October 31, 2015, 04:59:48 PM

[ Edward Turner designed 199cc tiddler (the Triumph Terrier)



Sorry to be a smart arse but the Terrier was 149cc

Title: Re: BSA B40
Post by: iansoady on November 01, 2015, 10:05:56 AM

I was wondering who'd spot that one.......