A trio of teasers

Tony Melo asks for my opinion on three matters: powder coating on engine cylinders, whether belts are better than chains and whether sealing O-rings in a rear chain is a good idea.

Phew; a lot of this is down to personal opinion, Tony. I avoid powder coat on an engine. It’s a tough finish, but I worry about it insulating the heat – especially gloss finish, which allegedly reflects the heat back into the engine. I prefer to brush (or spray) matt or satin heatproof.

Belt drive is very popular, but I don’t feel chains are enough trouble to be worth the expense, given the parts you need to change. Apart from oil leaks, the usual Black is black – but matt may be better than gloss

problem with primary chains is selftightening on separate-gearbox bikes – but this is due to torque pulling the gearbox back, which presumably happens just as easily with a belt.

But while a chain should have a little slack, belts are permanently under tension, which can place undesirable load on bearings – especially if the bike stands for long periods without being turned over. I’d say the only real advantage of belt is that it saves maintenance, but... well, isn’t that just being lazy?

The O-ring chain reduces the need for regular lubrication, but the sealing O-rings make it wider, which makes it weaker – that’s why racing bikes often use narrower chains than road models; wider rollers improve wear resistance but not strength. So with an O-ring chain, thicker side plates are fitted which, added to the O-rings, makes the chain very wide. On older bikes, designed for relatively thin chains, this promotes rubbing on engine casings and chainguards so I don’t feel the advantage outweighs the problems.