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1972 Model Year BSA B25T Replica

Posted: Sat Dec 02, 2017 9:43 pm
by JB
1972 B25T.jpg
I've had the makings of a B25T in bits for many years and I finally got round to rebuilding it this year :grin:

To be honest I'm not a great fan of the 1971 models grey frames and looking in Brad Jones excellent book "BSA Motorcycles: The Final Evolution" there is the only surviving picture of the proposed 1972 BSA B25T Victor Trail, one that we all know never made it into production :cry: We also know that there was a 1972 BSA B50T that did get made so the parts needed should be available. The most obvious difference is with the mudguards that were chrome plated for 72 unlike the painted ones in 71 and is yet another reason to go this route as I also really like the look of them. I got lucky and bought a new old stock chrome rear mudguard so was off to a good start. Next up was the electrical box mountings and brackets as the 72 models and late 71 models had a different arrangement that also moved the horn from the RH to the left hand side, fortunately Peter Quick came to the rescue and all the right parts winged their way back from the states. Next up was the rear brake arm and return spring, they were longer for 72 and I bought new ones from RIPE Motorcycles on ebay.

I've not done every change that differed between the 71 & 72 models, so the fork legs still have the rib that was removed for 72 although it is still present in Brad's picture of the prototype? Another difference was the exhaust outlet was curved away from the indicator for 72 where's mine's still straight, ala 1971. The colour scheme for 1972 B25T for 1972 was new and similar to the 500 in that the side panels were painted white and the tank had a candy side stripe with a white centre stripe. Brad very kindly emailed me the photo which I had a photoshop expert adjust the tones to get as close as possible to the intended colour. This though presented a problem because to get the tank professionally painted I was quoted £375, it would have been perfect but the problem for me is that whilst I'm lucky enough to live in Devon England (hello to Mr Grout) where we have a good network of green lanes and I am very active in this hobby which I enjoy immensely and building this bike would bring two passions of mine together. There is no way that I could build this bike and not go trail riding on it so the paint cost was an issue because I know it will not last and will need either touching up or redoing it so the cheapest option by far was a rattle can from RS Paints which is what I did in the end. The problem there is that spraying a Candy finish with an aerosol is not easy and I seemed to always end up with an even coat that was too thick and the wrong shade :???: It's something I can live with though as I can at least redo it myself as and when :cool:

I'm not going to give a blow by blow account of the rebuild as I've already done it and you can read it <HERE>

I had a major problem when I finished it as the carb jetting was way out and the bike hit a 8-stroking misfire wall @5000rpm the carb was in really good condition and was rebuilt with all the latest improvements and seemed fine as the bike started easily and ticked over perfectly. Rather than ditch the original exhaust that seems to be the easiest way to resolve the problem I didn't want to do that for a number of reasons, one being wanting to keep the noise down whilst trail riding. The cure was to fit a wideband sensor which showed how extreme the richness was. I've not got it perfect yet but its so much better and it runs really well now even with the original silencer.

The finishing touches were the transfers and Classic Transfers were extremely helpful and made the special side panel 250 Victor transfers in the same style as the 1972 B50T transfers but in a colour more in tune with the tank side stripe colour as they are on the 500 model.

Finally I would like to thank Midgie from this forum, when I was really stuck for the final few parts he came up trumps everytime and I am very grateful for his help :thumb :thumb :thumb And a special mention to Brad Jones, he's been very helpful to me and his knowledge of these bikes is probably second to none, just like the books that he writes on these great bikes :thumb :thumb :thumb
I finally got to go trail riding on this bike last weekend, I was nervous, as I was worried it might prove to be a poor trail bike, we have some tough technical lanes here in Devon and yet the bike has,so far, proved itself to be a very accomplished trail bike :grin: :grin: :grin:
Above should hopefully be a link to a video of this rideout with Sean on a XR200, my daughter who has passed her bike test and enjoys going trail riding with pops and Paul on his 2001 WR400. For those who don't know, trail riding is not competitive, it is all about being out enjoying the countryside on a small trailbike, it's also harder than it looks and many people coming from road riding can struggle to adapt as your wheels have a habit of going in different directions to where you want them to :shock:

Cheers John

Re: 1972 Model Year BSA B25T Replica

Posted: Sat Dec 02, 2017 10:32 pm
by minetymenace
Great to see it getting dirty, thought you were going to jump that deer fence Steve McQueen style, and was that the beast of Tiverton at 13:45? Looks like fun.....

Re: 1972 Model Year BSA B25T Replica

Posted: Sat Dec 02, 2017 10:57 pm
by JB
Deer fence jumping next time out :lol:
It was something that ran out and we woz miles from anywhere at the time <201 ...Beast of Tiverton it is :idea:
Lots of fun, I'm lucky... I can head out in three different directions and pick up some incredible lanes :smile:

Re: 1972 Model Year BSA B25T Replica

Posted: Sun Dec 03, 2017 1:05 pm
by midgie
I'm loving you're b25t jb cracking job there, but I knew it would be!

Re: 1972 Model Year BSA B25T Replica

Posted: Mon Dec 04, 2017 10:18 pm
by JB
Cheers Midgie and once again many thanks supply all the final parts needed to finish this bike off :grin:
When I get chance I'll do a little write up on the engine there's a few new bits in there ;-)

Re: 1972 Model Year BSA B25T Replica

Posted: Mon Dec 04, 2017 10:51 pm
by lathejack
A great looking bike, which looks even better with the big 8 inch brake you have on the front. Do you notice the extra weight of the big front brake whilst trail riding, or does it make no difference?

I read your write up of the bike, and you said you went from a T140 down to a B25T. I have sort of done the same thing, having a T150 and a few T140's over 27 years ago and nothing since until I bought a B25 Starfire and a B25T over the last couple of years.
The Starfire, and in particular my B25T are so enjoyable to own and ride that I don't miss the bigger bikes one bit. But of course I just couldn't resist buying a B50T as well.

I look forward to your write up about your B25 engine.