STEP -BY- STEP
Getting an S27 back in one piece
1 While I was sorting out the bits, Lewis set about scraping off the incredible amount of oil and dirt stuck to the engine and washing it with white spirit.
2 No chance of a spark from the magneto; the insulation has a finite life span – a lot less than 92 years! Damp’s a killer too; it’ll need a rebuild before the bike will run.
3 Original two-lever AMAC carb has two cables and two slides instead of a needle. Takes a bit of getting used to, but if not badly worn they work well,.this one’s OK.
4 But, chewed and seized, the squareheaded jet holder was a problem. A firm grip in good vice jaws will sort it; the nail prevents the hole up the middle getting crushed.
5 Unscrewing the jet holder reveals the screw retaining the ‘sprayer’ that replaces a needle jet in these carbs. These holes must all be clear.
6 Separate mudguard tail section facilitates rear wheel removal. There were a couple of cracks which were worth repairing before giving it to Lewis to paint.
7 The steel is very thin to keep weight down, so welding is a delicate business. I struggle to make it look tidy, but it comes out OK once it’s been ground back.
8 Lewis got busy with the brush and satin black paint for exterior metalwork. It gives a finish that, after a few miles, blends in well with remaining original paint.
9 Les had used similar paint on the bits he’d already painted. Lewis queried the eye-bolt used to hold the saddle tubes to the main frame; it doubles as a sidecar fixing.
10 I made some double-ended bolts for the rear frame connection. Not standard, they allow you to remove the mudguard without the frame collapsing.
11 Les had started taking the gearbox to bits, probably because he’d drilled out the cotter pin and damaged the kickstart shaft. I welded it and filed it to shape.
12 I stripped the rest of the ’box, but everything looked good inside. Now the fun bit: pouring in semifluid grease from my supply – luvverly stuff!
13 One of the great things about Lewis is he doesn’t mind getting stuck in and getting his hands dirty, as you can see. On with the toolbox...
14 ... and then the two-part rear mudguard. This paint’s fast-drying, but when you’re not after a shiny finish an odd finger mark doesn’t matter.
15 Now the gearbox could go back into the frame. Apart from a longer mainshaft, it’s the same gearbox as the 350cc models and is closely related to the wartime M20 model.
16 I copied the original registration letters still visible on the repainted plate in cream enamel. Don’t worry signwriters – I won’t give up the day job!
17 The clutch looked good, apart from this broken stud. It’s rivetted into the pressure plate and holds the outer dome that takes the load of the six springs.
18 I screwed in another stud, but before peening the rivet end over, screwed it into a domed nut to support it, so I didn’t bash it out of the other side.
19 The clutch is way beefier than the smaller single spring unit on a 350 model. The plates are in fantastic condition, so I just washed and reassembled it.
20 The flat oval key was missing, but it’s the same as post-war models and I had a spare so Lewis fitted it to the shaft and began tightening the nut.
21 The sprocket of the engine shockabsorber spins freely on the crank. It’s secured by a springloaded cam so the spring calms the engine punch.
22 It took a bit of brute force from yours truly to compress the spring enough to start the nut; once tight there’s a lock nut to go on top.
23 Exhaust pipe just pushes onto the port. It’s not bolted anywhere – it’s held up by this bracket, like a guttering support, on an engine bolt. Neat.
24 These zinc alloy sight-glass units are usually broken but not this one. I recently learned that pressing down on the knob squirts oil on the primary chain.
25 Final job was to fit footrests and brake pedal. Heel-operated pedal usually goes with footboards, maybe the first owner specified footrests instead.
26 It’s 5.30pm. Just time to throw the saddle in place for the final photo! Thanks a lot Lew, you’ve been a great help and that’s a well-earned cuppa!