The initial test ride revealed a lively performance from the bike, with good handling and good brakes too. It felt a little lumpy when bimbling along with the throttle almost closed, but I put that down to the fact that it had been standing for a few years; I don’t think the original owner had ridden it since before lockdown.
Once I rode it home though, some other issues became evident too. I’d hoped a decent ride would actually clear the surging, but it didn’t. I’ll post some repair pages to follow this one as I progress through the work needed.
The main issues were:
- The lumpiness, or more accurately ‘surging’ that was occurring at low throttle settings, made the bike quite uncomfortable to ride at a constant speed through the streets. I doubt the original owner would have been happy with this, so I put it down to a dirty or partially blocked pilot jet. I later discovered the carburettor on this bike was the wrong one, it should have an Amal Monobloc 389/12 but has a 389/27 which has a 1/16 of an inch smaller bore. The pilot jet is also a size 25 when the specified size is 30…that could also cause the surging. More later…
- The battery wasn’t charging. When I test rode the bike, the lights worked, as they did when I set off home after buying it. They were out when I got home and the battery was flat. I later discovered that the rectifier had an open circuit diode and that one of the stator wires was open circuit. There is more to this story to come!
- The front tyre was perished. I assume with standing, the rubber has reached ‘end of life’ and the side wall was cracked. Chances are the rear one isn’t good. I’ll fit a new pair of Pirelli MT43s, new tubes and rim tapes.
- On checking some squeaks, I found the rear chain to be probably the most worn chain I have ever come across. The sprockets look okay, but worn chains ruin sprockets and can snap.
- The horn button had stopped working. It was held on with a tie wrap as the metal clips were missing…it wasn’t making a ground connection.
- The large bolt holding the silencer in place was missing altogether…it’s the same size as a pillion footrest stud. Luckily the silencer hadn’t fallen off on the way home.
- In the primary chaincase, there is supposed to be enough oil to touch the bottom of the chain. On draining the primary chaincase I found about half a china tea cup full of dirty black oil, and the chain was as tight as a drum. What’s more, ALL of the fourteen screws holding the outer cover on, were little more than finger tight. Don’t mention the black silicone sealant either.
- The rear brake actuating arm passes through a bush in the brake plate. To describe the expander shaft as ‘wobbly’ really doesn’t do it justice. That will need doing when I change the tyre.
- The brake light hadn’t been working. The brake light switch used on these bikes relies on a sleeve which fixes to the brake rod spring…the sleeve on this bike had slid up the spring.
- Every now and again, the speedo would drop to zero then flick up before settling again. This is a common problem caused by the speedo cable inner sticking…normally it easily fixed by checking, cleaning and re-lubricating. A slight kink in the cable can cause this…but there’s more!
- Update: I discovered there was absolutely no oil in the gearbox to speak of.
- Update: The battery died completely when I tried to charge it…I’m guessing it had been left flat for quite a number of months or years.
- Update: I discovered the grease nipple for the speedometer drive was missing and the hole left open to the air. I cleaned out the hole, installed a new modern nipple and injected grease. It’s likely that the speedometer drive will need replacing.
- Update: after repairing most of the problems, the sparks suddenly decided to go on strike! I’ve ordered a new HT coil, but have also e-mailed BTH.
So, there are quite a few issues to attend to. The original owner might not have been aware of some of these, but I have to assume he’d just forgotten about the others as the bike hadn’t been ridden for so long.