Is This Motorcycle Cursed? A BSA B50 Story

Story and Photos by new Contributor Scott Rook

I had wanted a BSA B50 for many years. They were the final distillation of BSA’s unit singles that won World MX Grand Prix championships with Jeff Smith in the 1960s and were the last competitive factory four stroke MX bikes in the early 1970s. CCM and Cheney built special framed purpose-built racers around the B50 engine that kept them competitive into the mid and late 1970s. The B50 also had the weirdest and one of the most beautifully shaped alloy gas tanks ever conceived for a motorcycle. It wasn’t exactly round but it wasn’t rectangular either. It was dubbed the lozenge. Triumphs had Pear shaped tanks and Harley had Tear Dropped tanks, BSA came out with a cough-drop shaped tank. The B50 was also recognized as one of the last great British singles in a long line of bikes that stretched back to the early teens and twenties. British singles won Grand Prix Championships with great riders like Geoff Duke and John Surtees. Names like Comet, Manx, Goldstar, Venom, Thruxton and Victor were all great British singles. The B50 also performed admirably in road racing and endurance racing, often bettering larger displacement bikes. I wanted a piece of that heritage.

The rebuild started immediately. The night I brought it home, I took it for a quick run around the block and then started taking off all the stuff that had been done to it over the years. Within a few days the engine was out and the frame was getting stripped for powder coat. We have long winters in western New York which becomes rebuild season. The goal was to have my Dick Mann approved BSA B50 D/R ready for spring. I sent the engine to the foremost rebuilder of B50s in the U.S. Ed Valiket of EV Engineering. Everything else I would rebuild myself. Rebuild season is a time of hope and optimism. All the parts you have gathered start to come together to form this thing that has only existed in your brain for years. Winter turned to spring and then summer. The B50 wasn’t ready. The engine was still in another state as was the alloy gas tank that I had sent out to have the dents removed. By August everything had arrived and the drive to complete the bike was in full swing. I took it out for its maiden voyage on August 2, 2018. The bike wasn’t finished but the only things left to do were more cosmetic than functional.

Restorations are never complete when all the parts are done, and the motorcycle is back together. Restorations are really complete after all the running issues have been cleared up and the tuning has been completed which usually takes some weeks and miles. My B50 showed some issues on its first run outside of my neighborhood. The gearbox was giving false neutrals and I couldn’t get it into 4th gear without it popping back out. I thought the gearbox might have some wearing in to do or maybe the clutch needed attention. The other problem was a flat rear tire about 20 miles from my house. The tube stem had been ripped out. I had decided against running a rim lock on the rear tire. My mistake. Clearly this bike needed some more attention. The dirt trails would have to wait. It was August already and I had other bikes to ride that didn’t give false neutrals. The late summer and fall would give way to winter soon and if I wanted to maximize my riding time left then I would take the Triumph or the Dunstall CB750. The B50 got put away until rebuild season started again.

It worked, kind of. I still would get a false neutral once in a while, but I think it was down to the shift lever not being in the ideal position and not getting a good purchase on the lever. The new old MCM Spark Arrestor sounded great, but it would pop and sometimes really POP on deceleration. Probably an exhaust leak. The bike ran great after about 15 minutes of me panicking that I would downshift rather than brake. There were no flat tires, it ran great below 2,000 rpm, and the rear rim is in one piece as far as I know. There are still some things to be done. When I got home there was a noticeable oil leak which is down to the frame being overfilled. I added oil after it wet sumped. My mistake. And the exhaust has to be sealed. I think the cursed bike might actually not be cursed anymore. I didn’t manage to actually get lost, but I rode some roads that I had never been on before. This bike needs further miles. Remember all restorations are only finished after they have been tuned and all the issues worked out. This bike took 4 years after its restoration before it was actually finished. It might not be, but it kind of feels like it for now. I might make Dick Mann proud yet and finally ride to one of those trails that don’t really exist in my part of the world (unless you trespass on county land). The Hammer may still live up to its name and thump once more.