And the fight to get complete continues.
CVMG September monthly meeting
Eleanor and I attended the September CVMG meeting for London this week and presented the BSA project at their request. I brought along the DELL projector I’d repaired a couple of years ago, and we threw our PowerPoint up on the wall. I think it’s safe to say everyone now knows who the “technology people” are… lol.
Attendance was solid, and folks seemed genuinely pleased with the story, the details, and the progress (or at least the drama) of the B40. I shared a link to the blog so they can subscribe and follow along—assuming, of course, they can wrestle with the mysteries of the internet.
A great side-effect: now everyone knows what’s on my parts shopping list. That means more eyes on the hunt! Pete, one of the members, even mentioned he might have a silencer (aka muffler) that would fit. If that pans out, all I’ll need is the connecting pipe from the engine to the silencer—whether that ends up being found, bought, or fabricated. Either way, it feels like a promising lead.
Speedometer drive
The BSA B40’s speedometer drive is one of those little gadgets that you don’t think much about—until it isn’t there. It’s a Smiths-style mechanical unit, tucked away on the rear wheel axle, quietly converting every turn of the wheel into a spinning cable that feeds the speedometer.
Inside, a drive ring turns a worm gear, which spins the inner cable, which spins the speedometer needle. Simple enough in theory. In practice, it’s a fiddly piece of kit that can slip, bind, or just decide it’s had enough after 60 years of service. Many riders from back in the day will remember watching the needle bounce around like it was measuring earthquakes rather than road speed.
But when it works, it’s a clever little link between man, machine, and velocity—one that was shared across many of BSA’s unit singles, including the B40. And it’s matched to magnetic Smiths speedometers, which means the right drive ratio, cable, and sleeve nut all need to play nicely together.
When I got this bike, the speedometer cable was already disconnected. That makes me wonder if my late father-in-law had already had his own battles with this setup and decided to quietly declare a truce. Time will tell—my next step is to hook the cable up to a drill and see if the speedometer needle even twitches. If it doesn’t, well… that’ll be another chapter in the saga.
So, while some might dismiss it as just another widget, I like to think of it as the unsung hero that keeps you from being “that rider” explaining to the constable, “Well officer, I didn’t realize 45 felt so much like 65.”
My goal here was to remove the speedo unit so that I could remove the then sheet metal decorative cover. Would be required to access the spokes if removing and needed to clean both. It should just slide up, but I struggled to gently pry it with 2 and 3 lifters. After discussions with everyone gentle pressure, light oil, persuasion was the suggestions (no tricks) and don’t use heat or break the unit… OMG
Speedo to be continued.. Friend arrived for a late afternoon Virtual Pinball competition in the basement… BSA later.
Saturday.. continued
One thought I’m entertaining is the idea of sandblasting and powder-coating the existing rims, spokes, and center hubs. That would give me a solid “version 1.0” of the rebuild—good enough to get the bike rolling and respectable—while I keep hunting down new chrome rims for a proper “version 2.0.” The math is simple: rims are about $150 plus shipping each, then I’d still need new spokes, a cleaned-up hub, and someone skilled enough to true the whole assembly. Powder-coating what I have now could save a lot of time and money while still looking sharp-ish.
My BSA friend Mario (from CVMG) offered to loan me his professional tire removal tools, so when we met up at the weekly McDonald’s coffee gathering, we did the handoff in the parking lot like a couple of shady parts dealers. We’re also heading together to the Mohawk Racetrack swap meet on Sunday morning—perfect timing to strip these tires off and see what I’m really working with.
Side-tracked: Of course, before I can focus on the BSA, my neighbor Cal roped me into helping with his “new to him” 1982 Yamaha XS400. He recently got his M2 license and was excited about his vintage purchase (yes, it technically qualifies now—yikes). The problem was it refused to start, either on kick or electric. He’d told me the electric starter didn’t work, but I suspected it was more a case of a weak battery than dead electronics. Sure enough, after a night on my trickle charger, I hit the button and it fired up. We used our planned time and tackled a front brake job and made a punch list of what he’ll need before a Service Ontario inspection. A good day’s progress for him.
Now—back to the BSA. Tires to come off, and time to put that speedometer drive mystery to the test.
The tools are in the collection of images above—the pry bars and the hammer for breaking the bead (or persuading stubborn rubber to move when needed). They worked beautifully, and the job went surprisingly well. The rubber is in decent shape, but I’ll definitely be scouring the swap meet for tires that are a little younger than half a century old. Still on the to-do list: getting the bearings and shafts out of both wheels.
I set up the rear wheel on a 4″x4″ block and was able to drive the shaft down, which let the speedo drive pop right out. (Naturally, I only remembered to take the photo after flipping the rim around—classic move.)
Both tubes look fine—one even has an old patch—but since they’re holding air, I’m calling that a win.
As a bonus, I also managed to wrestle off the decorative hub covers. That took some creativity: two nail puller tools working around the edge while I blasted the cover with a heat gun to soften the ancient goop holding it in place. A few bent edges near the spokes needed some coaxing too, but eventually they surrendered.
After a few hours I had both rims broken down. One still has the shaft and two bearings stuck inside, while the other is clinging to a single bearing. Looks like it’s time to invest in some proper tools—brass drifts and bearing installers—if I want to finish the job cleanly.
And yes, at this point I think the bike is keeping a running tally of how many tools it can trick me into buying.
So that’s where the B40 saga sits for now: parts spread across the bench/floor/garage, bearings still to be evicted, rims stripped down, and a speedometer drive that may or may not cooperate when I spin it with a drill. It feels like progress, though in the same way a Highlander might feel “progress” climbing Ben Nevis in the rain—you’re not sure if you’re winning, but you’re definitely wetter and tireder than when you started.
Still, every step forward matters, and with swap meets, kind friends lending tools, and the occasional bit of stubbornness, this old BSA will come back together. In the meantime, I’ll keep smiling, keep hammering, and keep reminding myself: it’s only vintage motorcycling—nae brain /brian surgery.
Or as a Scot might say, “If ye cannae fix it wi’ a bigger hammer, maybe ye dinnae own enough hammers.”
Fingers crossed for the pending Swap Sale….