samwisemcg Posted August 30, 2018 Report Share Posted August 30, 2018 I was wondering if anyone could help me identify a bsa frame. The engine is a b40 and I was told the frame is a b25. There are a couple of things that seem strange. The log book has it down as a March 65 bike, but I am pretty sure the earliest b25’s were 68. I have the frame number in the log book, but I can’t find it on the frame, does anyone know where it should be. Also it seems like the frame has been modified. There should be 2 center posts, from the foot pegs up to the front of the seat. It seems like these have been modified to one center post. After having a look on google I can see a couple of b40 trials bikes that look the same. Does this look like a modified b25 frame, or maybe a c15 frame? Any help would be much appreciated. Thanks Sam 1 Quote Link to comment Share on other sites More sharing options...
windlestone1 Posted August 30, 2018 Report Share Posted August 30, 2018 That's nice. Try the BSA Otter site, Charlie the site owner is very helpful and has a wealth of knowledge and archives he refers to 1 Quote Link to comment Share on other sites More sharing options...
b40rt Posted August 30, 2018 Report Share Posted August 30, 2018 My B40 has the frame no on the left (as your sitting on it) front engine mount. 1 Quote Link to comment Share on other sites More sharing options...
trialsrfun Posted August 30, 2018 Report Share Posted August 30, 2018 (edited) I think you may have a modified WD BSA B40 frame. The two tubes from the rear of the tank to swing arm pivot have been reshaped attaching much lower so as not to rub the ridrrs legs also I think the head angle has been altered, look at the down tube above the engine mount. You have a good looking bike which ought to work rather well. Edited August 30, 2018 by trialsrfun 1 Quote Link to comment Share on other sites More sharing options...
samwisemcg Posted August 31, 2018 Author Report Share Posted August 31, 2018 17 hours ago, windlestone1 said: That's nice. Try the BSA Otter site, Charlie the site owner is very helpful and has a wealth of knowledge and archives he refers to It's funny you should mention that. I have spent a lot of time on that site this week, it's a great read. 16 hours ago, b40rt said: My B40 has the frame no on the left (as your sitting on it) front engine mount. I did check here and can't locate it. i wonder if the paint on the frame is so think it has covered it up. 12 hours ago, trialsrfun said: I think you may have a modified WD BSA B40 frame. The two tubes from the rear of the tank to swing arm pivot have been reshaped attaching much lower so as not to rub the ridrrs legs also I think the head angle has been altered, look at the down tube above the engine mount. You have a good looking bike which ought to work rather well. Thanks, I did look into the b40 frame, but they have a removable rear subframe and my bike doesn't. I haven't had the chance to ride it in anger yet as it still needs running in. I'm looking forward to getting out on it. Quote Link to comment Share on other sites More sharing options...
trialsrfun Posted August 31, 2018 Report Share Posted August 31, 2018 1 hour ago, samwisemcg said: 1 hour ago, samwisemcg said: Thanks, I did look into the b40 frame, but they have a removable rear subframe and my bike doesn't. I haven't had the chance to ride it in anger yet as it still needs running in. I'm looking forward to getting out on it. The earlier road bike B40 like the C15 had a detachable rear subframe. 1 Quote Link to comment Share on other sites More sharing options...
samwisemcg Posted August 31, 2018 Author Report Share Posted August 31, 2018 (edited) Thank you. That definitely looks like it could be the frame. Thanks for the help. Edited August 31, 2018 by samwisemcg Quote Link to comment Share on other sites More sharing options...
trialsrfun Posted August 31, 2018 Report Share Posted August 31, 2018 The WD B40 frame which was all welded was based on the Victor scrambler this frame was used on the later BSA works trials bikes. Jim Susans of Bikecraft modified many WD frames in the way that yours has been done. http://www.bsaotter.com/jim_susans_bikecraft.html 1 Quote Link to comment Share on other sites More sharing options...
samwisemcg Posted August 31, 2018 Author Report Share Posted August 31, 2018 4 minutes ago, trialsrfun said: The WD B40 frame which was all welded was based on the Victor scrambler this frame was used on the later BSA works trials bikes. Jim Susans of Bikecraft modified many WD frames in the way that yours has been done. http://www.bsaotter.com/jim_susans_bikecraft.html Thanks, thats really helpful.I will definitely have a read through this page when I get a chance. There is something else different about my bike. It has an alloy barrel and it was said that it could be a works barrel/engine. I can find aftermarket alloy barrels, but they all have 10 fins. My bike has a 9 fin alloy barrel. Strange... I guess it doesn't really matter what it is, as I couldn't be happier with the bike. 1 Quote Link to comment Share on other sites More sharing options...
section swept Posted September 1, 2018 Report Share Posted September 1, 2018 What ever frame it is the bike looks brilliant. 1 Quote Link to comment Share on other sites More sharing options...
b40rt Posted September 3, 2018 Report Share Posted September 3, 2018 @samwisemcg 1 Quote Link to comment Share on other sites More sharing options...
samwisemcg Posted September 6, 2018 Author Report Share Posted September 6, 2018 On 9/3/2018 at 11:46 AM, b40rt said: @samwisemcg Thanks for this, I really appreciate it. I'll take a look this weekend and see if i can locate it. Cheers Quote Link to comment Share on other sites More sharing options...
section swept Posted September 6, 2018 Report Share Posted September 6, 2018 (edited) If you haven’t already done so, have a look at Brittania Motorcycles where you find and see a very knowledgable person carrying out modifications and alterations to frame, engine and everything else virtually. But again I must say that your bike looks the real business? Edited September 6, 2018 by section swept 2 Quote Link to comment Share on other sites More sharing options...
samwisemcg Posted September 8, 2018 Author Report Share Posted September 8, 2018 On 3 September 2018 at 11:46 AM, b40rt said: @samwisemcg Thank you, I found the number in the end and it is a b40 frame. It is under some thick paint and only just visible. I probably wouldn't have found it if I didn't know where to look. Thanks for the help all! 1 1 Quote Link to comment Share on other sites More sharing options...
Olibirch Posted November 5, 2020 Report Share Posted November 5, 2020 Its a 370cc. My partners blind late step dad built it. Gary Hewlett ! Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.