The term ‘barn find’ is frequently used inappropriately, but this time Stuart Francis really did pull a vintage motorcycle out of a crumbling barn where it had been gently decaying for decades…
This story started in 2014, as told in part back in RC159. Mossy, a local character with an eerie ability to unearth old motorcycles, told me and my friend Donald about a stash of barn-find motorcycles that were for sale. The 10 hour drive was well worth it. I bought a 1946 Velocette MAC, a 1924 L24 BSA and a 1915 Douglas; Donald bought a 1918 BSA and a 1924 Douglas CW.
After sorting out the Velo MAC, I turned my attention to what had been sold as a 1926 L26 3½ hp 350cc sidevalve BSA. The machine was a genuine barn-find and I decided to try to keep as much of the patina of its age as possible. By far the biggest problem was that the back wheel was missing, as were the exhaust pipe and magneto. The rear mudguard was also so damaged and twisted that it could have been used as a very large corkscrew! The engine and gearbox looked like they needed some attention, but fortunately it came with a load of secondhand parts; three engines, a refurbished barrel with a new piston, four gearboxes, a couple of clutches and some other spares.
The engine was quite an easy job. After removing the rather tired top end I found the bottom end was not too bad; fitting the refurbished barrel and piston got the project off to a flying start. What did take time was making the cylinder head valve covers and sealing rings. Having machined a piece of brass to the right shape, screw-cutting the fine thread on my worn lathe was a bit fiddly. It needed a couple of passes with a thread chaser before they felt right. Silver soldering a piece of bored-out hexagon brass bar onto the top of the valve cover finished them off. The sealing rings were just very thin pieces of aluminium tube that I annealed to soften them up.
The gearbox was next. After replacing the output shaft ball bearing and a rather worn gear selector, it all seemed to go together quite well… more on this later. A suitable old Lucas magneto was found in my stock of spares to replace the missing item. A quick rebuild, including re-magnetising, produced a healthy spark.
The badly twisted rear mudguard was held together by the number plate mounting bracket. It took a lot of work to tease it straight, weld up the cracks, tap out the larger dents and paint it in an industrial, semi-matt black that looks like old worn enamel. The rear carrier looked all right until it was removed, which revealed that it was twisted and had a number of rust holes on the underside. Some deft work with the welder and grinder, followed by clamping it in the big vice and applying pressure through a piece of timber, soon sorted it out. A quick coat of my favourite paint finished it off.
The front forks were stripped down to check for wear. BSA used an unusual arrangement; the side links have short tubes brazed onto them that run in bushes in the steering head arms and fork legs. The tubes and bushes were slightly worn, but were OK for a machine that might just exceed 45mph and will only be used on high days and holidays. I did replace the four very long bolts that held the side links in place because it looked like somebody had used an 18” Stilson wrench to tighten them.
By far the biggest job was fabricating the rear wheel; a narrow 19-inch, WM1 rim rear wheel from my pile of bits seemed like a good start. It quickly became clear that to centre the wheel rim, get the rear chain inline, and the brake plate in place, the rim had to be re-spoked with a different offset and a dished rear sprocket manufactured. The sprocket needed three layers of metal to get the right amount of dishing, like three levels of a pyramid. Keeping the sprocket
teeth concentric and true to the centre while welding it all up was a bit of a challenge. After a bit of trial and error and a quick skim in the lathe, it all started to line up and did not look out of place.
Originally the 1924 L24 had dummy rim brakes at both ends, but at some point the front brake was replaced with the slightly later, internal expanding band brake. The spring steel brake band is anchored at one end and the brake lever pushes the other end, expanding the band and forcing the friction material onto the inside of the brake drum. The friction material was rather worn, so after some initial discussions about bonding, a local friction material supplier riveted on a new lining. The rear brake is an early BSA Bantam item that does not look out of place.
The exhaust pipe was an old Matchless G80 pipe that was severely cut and shut to fit the tortuous path it had to follow. Leaving it outside in the rain to rust added to the look…
All the bits were assembled together and the pipework connected, and then it was time to start putting the oil and petrol into the tanks. The first concern was that there seemed to be a small but persistent oil leak coming from the front left-hand side of the oil tank. Initially I thought it was the hand oil pump pipe union, then I thought it was a split seam, but it eventually turned out to be a couple of tiny rust holes in the bottom of the tank.
The petrol tank was OK but petrol shot out of the AMAC carburettor when the fuel was turned on. Suspicion fell on the float level, and after some head scratching it turned out that a later float needle had been fitted. Tony Warren, who owns a very nice 1928 ohv model, experienced the same problem and suggested fitting a hole-punch eyelet on the float needle shaft to adjust the fuel level. This helped considerably, however there was still a steady slow drip from the bottom of the carburettor. Further delving revealed the float bowl union to the carburettor had been damaged and someone had tried to file the faces flat. Some tedious work with needle files has improved things no end but it still gets slightly damp at the joint.
Initial attempts to start the machine were very frustrating. Tantalising occasional glimmers of ignition convinced me that success was just around the corner, but it wasn’t! Whipping out the plug revealed a weak and intermittent spark and some very sooty deposits. With the bike back up on the work bench, the problem became clear. Some of the oil from the leaking oil tank had got into the magneto.
After cleaning out the magneto I decided to take a slightly different approach to starting: no petrol but a shot of ‘Start Ya Bastard’ (an Australian brand of easy-start) up the carburettor. After a couple of kicks it burst into life and ran for 30 seconds. Repeating the process and then turning on the petrol after it had fired up got the machine running but clearly it was very rich, even with the air lever fully open. After further lowering the fuel level she would start and run reasonably well.
My first attempt at riding the machine was not the best experience I’d ever had. The re-covered oversize bicycle saddle was very uncomfortable. Raising it and tipping it forward improved things no end, but it still feels like I am sitting on the family jewels!
However my real concern was the gearchange. It was very difficult to engage first, and nigh on impossible to change gear when the clutch was pulled in, although clutchless changes were OK. Suspicion fell on the gearbox mainshaft end float, but initial checks with the clutch removed suggested all was OK there.
In a moment of desperation I rotated the mainshaft slowly and found lots of end float, then carried on rotating and it disappeared. It turned out the large flat-faced engagement dogs on the gears were touching and masking the true end float. A thicker thrust washer soon sorted it out.
I was exchanging emails with BSA-expert Rick in the UK about the gearbox problem, when he pointed out that the machine was probably a 1924 model. He cited the frame number, petrol tank construction, rear carrier construction and the lack of a damper on the front forks; all good indicators that it was an earlier machine.
The L24 was BSA’s cooking 350cc sidevalve, but it had a three-speed gearbox, clutch and kickstarter. It was relatively easy to operate and maintain – the handbook suggests setting tappet gaps with a business card! BSA also produced a 500cc sidevalve aimed at the sidecar market and a very nippy ohv version. In 1924 my 350 would have been fitted with beaded edge wheels, changing over to wired rims in 1926/27. It is worth reflecting how far machines had come in the previous 10 years, when direct belt drive was still common and most machines had to be push-started.
So what is it like to ride? A good tickle on the carburettor, slightly retarding the ignition followed by a couple of hefty swings, usually brings it chuffing into life. I give it a shot of oil from the hand pump at this point, and check to see if the oil from the engine pump is dripping in the sight glass and adjust the drip rate. The clutch is quite light and first gear goes in with a clunk. First is quite low so I quickly change up to second while juggling the throttle, air lever and gear lever which are all on the right-hand side.
Picking up speed slowly I slip it into third and, like a stately galleon, it cruises along at about 30mph. With the wide, bent-back handlebars the riding position is rather upright and the previously mentioned saddle makes its presence felt. The machine feels tall and slightly top heavy, although this may be rather more to do with my larger build.
Slowing down takes a bit of time and coordination. The front (expanding band) brake is rather weak, it may improve a bit when the new lining beds down. In its day, this brake was considered to be a significant improvement over the dummy rim brake! The Bantam rear brake is reasonably effective and is the brake I rely upon. However at some point you have to change down. I leave this as late as possible as it involves closing the throttle and air lever and letting go of the front brake to move the gearchange lever – all with the right hand. I have tried clutchless gearchanges with the left hand but with little success.
So the key question: was it worth the effort? I can only respond with a resounding YES. Once you get used to its foibles, the BSA is a real blast to ride on country roads, and the technical challenges only add to the enjoyment. I must admit I wouldn’t want to do much town riding given the slow acceleration and poor brakes but, that aside, I usually finish up with a big cheesy grin on my face while riding it. The only outstanding niggle is I have broken two kickstart springs so far and finding a replacement is difficult.
The BSA had its moment of fame when a local photographer, David Russell, needed help with a photoshoot for a family antiviolence campaign poster. He wanted an old motorcycle for a steampunk model to pose on, and the 1924 BSA L24 fitted the bill. The model arrived one Sunday afternoon dressed up in her steampunk outfit, complete with a hard leather corset which her partner then proceeded to tighten up – rather like that scene out of Gone with the Wind. She got on the bike with some difficulty due to the tight corset, and David took over 100 images of her on the BSA. She wasn’t keen on riding it as her experience is with modern bikes, and all its strange levers can be something of a challenge!
The start of the rebuild. Everything looks pretty encouraging from the front
Left: A rear view reveals that there is quite a lot missingBelow: The top end reassembled, complete with a refurbished barrel
Above: A stock of spare engines can only be a good thing
Nice and shiny; new valve caps
Part way through the rebuild, with the new rear wheel in place
Where the sparks come from. Mr Lucas’s meaty magneto
Oil control and sight window
When it was new in 1924, Stuart’s L24 sidevalve 350 would have cost £47.10s. These days, it’s worth more like £6000
One handy BSA, fresh off the bench
Tony Warren, who owns a very nice 1928 ohv model, provided advice and encouragement
‘Invest in a BSA for satisfaction, reliability and sterling value’ Or else…
It’s Cheesy Grin Time!
Although this may appear to be a simple machine, the rider has much to occupy both time and attention. Consider changing gear, for example
At 217lb, the L24 was one of the lightest bikes built by BSA at that time
Nothing unnecessary here. BSA built bikes intended for hard work and a long life