Attending to Tomos #1: chain

If it looks like this you'll probably need a new one

You can be pretty sure any machine that's sat around for a while unloved will have need of  serious chain maintenance and my little Tomos was no exception. The secondary drive chain was stiff, dirty and seized in several links.

Off it came and, after a wire brushing to remove the worst of the crap, into a bath of bubbling hot oil for twenty minutes. Putoline chain wax (the large dishes you heat on the stove) is the best stuff (or make your own cheap alternative with melted candles) but I'm using up a stash of chainsaw oil which is almost as viscous, warms to a thin oil which creeps into the links and cools to a thick coating that doesn't drip.

On this occasion though, no go. Despite freeing the chain it was pretty clear it was worn beyond redemption and fit only for the bin. Fortunately, the Tomos uses a moped-standard 415 chain which is super cheap. I bought a Triple-S 415H for less than a tenner on eBay. Out of the packet it has 120 links and a split link, and the idea is you shorten it to suit the application.
 

Moped motive matter: the ubiquitous 415 chain

Tomos A3s and A35s have 90-link drive chains so you end up with 30 links as a useful back-up if any seize in use. ’Course, with proper maintenance that shouldn't happen and nor should you mix and match new and worn bits of chain but make your own mind up, for this application I'm happy to salvage wherever I can…

To shorten the chain, count backwards by the required factor, mark the link to be removed with chalk and set to with a link splitting tool if you have one. I don't cos I don't like them. I use the old fashioned method of file and punch (or in this case, the slightly newer fashioned method of grinder and punch).

The best kind of chain splitting tool

File or grind the heads off the two pins of the link you want to remove and use a punch to drive them below their link plate. As you do so the plate will spring off, freeing the link and splitting the chain. It's far easier to do than describe.

At the machine, remove the spark plug, wind the new chain over the rear sprocket and towards the gearbox sprocket until a few links engage then use the kickstarter to rotate the sprocket and chain until it reappears beneath the bike. Join the now dangling ends with the split link provided.

Everyone knows this of course but… be sure to put the retaining clip over the link with its closed end pointing in the direction of drive.

Split link: closed end in the direction of travel

Chain sorted and with the bike still on the bench, I crimped a new 2.8mm female spade terminal to the rear brake light which previously, was shorting and stuck on. I also drained and refilled the gearbox.

Rear brake light switch required new terminal

This latter requires 220ml of transmission fluid. Out of the box, the Tomos ships with Type A. I use  Type F as do many other aficionados. Cheap, easily available and fine for purpose. Your experience may differ…

Good enough!