18
SEPTEMBER 2020
The Chain..... By Duncan Bennett, Member #4171
W
hat on earth is that? I hear all the >800 BMW crowd and most of the >=1200 of other marques (except KTM) asking. Well, back in your dim dark past when your parent or correctional centre warden decided you needed to become independent and get yourself off to a parole meeting, kindergarten or Sunday School, they taught you to ride a bike. Last time I watched the Tour de France, none of the competitors had a final drive hidden nicely inside some smooth looking swingarm, they had a chain. So if you ever had a bike, and it’s a rare kid that didn’t, you were exposed to a chain. A chain has many advantages; it is highly visible, able to shred the bottom of your school trousers, covered in a filthy mix of grease and what appears to be night soil, and will throw itself off at the most inconvenient moment such as when you are being chased by tough kids on dragsters. Same with motorcycle chains, although getting your school trousers stuck in one is a lot more difficult because you either threw them out or burned them 40 years ago. This article was inspired by a recent experience on the B2B16 , see that in a few pages on from here, when my chain was discovered to be very loose and starting to rub on the centre stand guard - a big risk of a major drama. This was not a totally novel experience, so “chain awareness” is important especially if you like doing long trips. Firstly, how long do you get out of a chain and sprockets? Looking at the original chains on our new bikes - Cindy’s 2015 BMW 700GS, 35,000km. On my Triumph Tigers, about 48,000km and 36,000km. On Cindy’s current Tiger 46,500km and still going OK.
MAINTENANCE CORNER Wildly different for chains doing similar duties on similar capacity bikes, but the range is usually somewhere between 30,000km and 48,000km. If you are over 30,000km, at least ask your service provider to give it a thorough check if you don’t like covering yourself in the grease/night soil mix. Don’t ask me how grease even gets on chains, we only use oil. All motorcycle manuals will describe how to tension the chain. The normal method is a bit motorcycle brand specific - some can be checked on the side stand, some on the centre stand, and some inconveniently have to be held upright off the stand while you try to check the tension and not drop the bike onto yourself or your partner’s Lamborghini. The usual allowed slack is between 25mm and about 40mm half way between the sprockets make sure you measure in the same place. Too far forward and the chain will push up into the swing arm, too far back and the rear sprocket will limit movement.
25mm - this more than precise enough
