A motorcycle drive chain is an astonishing piece of engineering. It handles huge loads, provides an enviable level of mechanical efficiency and does it all in conditions which are often far from ideal, getting pelted with water, salt and abrasive filth from the road surface. Regular checking and adjustment when needed is vital for the condition of the chain, it’s longevity and the smoothness of your transmission. Chains that break or jump off the sprockets due to lack of attention can destroy engine cases and, at worst, have you off the bike.
Tightening your bike’s drive chain should be the easiest job in the world, however it is remarkable the number of riders you see with a chain so slack it is virtually dragging on the ground. Here’s our guide on how to adjust it, with some top tips along the way.
Step 1 - The first thing to do is read your owner’s manual. There is no fixed rule when it comes to a chain’s tension, each bike is different so look in your owner’s manual to find out what the free play should be. Once you know what the slack should be, write it on your garage wall with a permanent marker so next time you won’t have to dig out the manual.
Step 2 - You only need minimal tools to adjust a chain, a few spanners and a ruler, however if your bike doesn’t have a centre stand you may need either a paddock stand or a mate to lend a hand.
Step 3 - With the bike’s rear wheel off the ground, loosen the axle nut and slacken off the adjusters by the same amount each side. Once the chain is nice and slack (or slacker than it was before you started!) do up the axle nut so it only has a very minimal amount of resistance then tighten the adjusters by the same amount each side, usually quarter of a turn.
Step 4 - Check the chain’s free play by holding the ruler against the chain at the bottom of its loop and then pushing it up and down to measure the movement. Don’t force it, just see how much easy movement there is in the chain. When you are happy you have the correct tension it’s time to check the wheel’s alignment.
Step 5 - Although most bikes have marks on their swingarm to help you these are notoriously inaccurate so instead measure from the centre of the axle to a fixed point on the swingarm. Check both sides are the same and hopefully this should mean your rear wheel is correctly aligned. You can measure it more accurately but this basic technique is good enough for a home DIYer.
Step 6 - Finally, before tightening everything up properly, give the wheel a good bash inwards to ensure the adjustors are properly located, double check the free play again and then tighten the axle nut. When tightening the nut always use a torque wrench set to the correct value (check your owner’s manual) and use your free hand to put some tension on the chain when you are tightening it.
By tensioning the chain as you tighten the axle nut you ensure the wheel doesn’t move and alter its position. OK, all done, nip up the adjuster nuts, lube the chain and give it a last check for tension and alignment. While you are on your hands and knees give the tyres a look over for tread depth and any damage and also check your brake pads for wear and your tyre’s pressures.
Chains do not always wear evenly, so when you are adjusting the tension, rotate the rear wheel and check the chain at different points. Adjust it to give the correct play at the tightest point. Correctly looked after chains on even the most powerful bikes will give long, reliable service.