Motorcycle chain maintenance
The drive chain, sprocket and chain wheel are wearing parts. Although modern O, X and Z-ring chain kits are capable of quite impressive mileages – sooner or later you will need a new chain and sprocket kit.
Wear test and chain maintenance
If you can lift the chain links on the sprocket several millimetres even though the chain has been correctly tensioned, or if the chain is obviously unequally elongated, then it's time it was scrapped. Bikers who are on the ball will always replace the complete chain and sprocket kit – because they know that a new chain will all too quickly adapt to the degree of wear and tear of the front and rear sprockets. O, X and Z-ring chains have permanent grease lubrication, which ensures that the pins inside the chain are always lubricated. Despite this, everything else must be regularly maintained using a chain spray (compatible with O, X or Z-ring). Only use a special cleaner, never thinners or petrol. If you want to ensure particularly effective cleaning and greasing, you can use a patented device. Encrusted chains can also be quickly and conveniently cleaned using a special brush. Don't forget: regularly cleaned chains last longer because dirt is abrasive and causes wear and tear, even if you regularly lubricate the chain.
Compared to O-ring chains, X-ring chains have lower power loss due to friction and offer vastly improved durability. Standard chains without O or X-rings are used more or less exclusively in motor sport nowadays. When you lubricate the chain (always on the inside surface), it's good to check the slack at the same time. To do this, turn the rear wheel by hand and determine the tightest spot – this is important because a chain that is too tight will ruin the transmission output shaft bearing – and that's an expensive mistake to make. Standard tension is roughly 2 finger widths of play in the centre of the lower chain run with the bike loaded and on the ground. The easiest way to check this is to sit on the bike and get a friend to test it for you. To alter the tension at the adjustment mechanism, first loosen the axle and jack the bike up. It is important to adjust evenly on both sides of the swing arm in order to maintain the wheel alignment. If in doubt, check the alignment using a long straight batten or a piece of string. The Profi Laser CAT chain alignment tester enables 100% correct alignment with laser accuracy, in seconds. Bear in mind that overtightened, worn or badly maintained chains can break – and that can result in a badly dented engine case, or even cause an accident or worse!
A drive chain is only as strong as its weakest link. Which is why we recommend fitting an endless chain whenever possible, particularly for DIY mechanics. If this is not possible because the swing arm has a top or bottom strut, use a rivet master link.
If you have no experience of chain riveting, this task is best left to the professionals! Only use clip master links on bikes up to 125 cc.
If you're not sure about this job, ask a professional for help or chat to your local bike workshop. After all, it is a question of your safety. Ideally, this is a two-man job. A second pair of hands helps prevent damage caused by your bike falling over etc.!
Replacing the chain and sprocket kit
Removing the sprocket and chain wheel
To get at the chain sprocket, you will first need to remove the footrest, the gearshift (note position!) and a cover. When you lift off the cover, watch out for a possible clutch actuator – try not to disengage it if possible. To secure the motorbike, put it in first gear and engage the rear brake (get your helper to operate the brake) so that you can release the sprocket, or clamp a tightly wound cloth between chain and sprocket. There are various types of sprocket fixture (central nut with tab washer, central bolt with tab washer, mounting plate with two smaller bolts). First remove the locking device (e.g. bend open tab washer), before loosening the fastening bolt or nut of the sprocket using a suitable socket ratchet wrench and a spot of elbow grease.
Remove rear wheel
Now remove the rear wheel. If you don't have a centre stand, please bear in mind that you should not jack the bike up at the swing arm for this job. Remove the chain guard and the rear hugger, if fitted. Loosen the axle nut and drive out the axle with a plastic hammer. Use a rod if necessary. Hold the wheel securely, and carefully let it slide to the floor, push it forward and remove from the chain. Make a note of the mounting location of the spacer sleeves!
Replace chain wheel
Unscrew the sprocket from the mount on the rear wheel. Here too, bend open any tab washers. You should always fit new tab washers and self-locking nuts. Clean the mount and install a new sprocket. Tighten the bolts crosswise, preferably using a torque wrench according to manufacturer specifications. Flatten any tab washers back down. Give the wheel a final check: Do all the bearings and seals still look in good working order? Is the damper behind the sprocket mount still correctly tensioned? Replace any damaged components.
Remove swing arm
Remove linkage and ...
Now comes the bit that many folk don't really enjoy - removal of the swing arm. However, a little bit of calm and patience go a long way with this job. First detach the brake hose from the swing arm, but do not remove it from the calliper or otherwise open the brake system! It is enough to remove the brake calliper rod from the swing arm and wrap the dismantled brake unit in a cloth and place it underneath the bike.
... swing arm.
The swing arm is now only connected to the bike at the suspension and axle. If your bike has twin-shock suspension, remove the lower fastenings from the swing arm. If you have a mono-shock, you may need to undo the linkage. Take a moment to look at how the suspension works, and decide which bolts need to be undone. Make a note of the position of all removed components! Finally, undo the axle nut of the swing arm and carefully push out the axle. This is generally well greased, so try not to let it fall in the dirt.
Installing new chain and sprocket kit
Replace chain sprocket
Now you can remove the sprocket. Make sure you remember its installation position – there is often a thicker and a flatter flank. You must re-install it correctly to ensure the correct chain alignment. An incorrectly aligned chain may break! Once you have thoroughly cleaned the surrounding area, you can fit the new sprocket together with the chain in the correct position. If necessary, replace the tab washer and fasten and the nut/bolt. This will be tightened later with a torque wrench.
Clean, grease and re-assemble
Use suitable cleaning agents to thoroughly clean all components of the swing arm and swing arm mounting. Grease all moving parts (bushings, bolts). If your swing arm is fitted with a slider to prevent chafing by the chain, this should be replaced if it has worn thin. Before replacing the swing arm, you need to re-grease the swing arm bearings. Always refer to the manufacturer's lubrication instructions. If at all possible, get someone to help you re-install the swing arm, so that while you are positioning the swing arm in the frame, your assistant can insert the axle. Next, replace the shock absorbers and, if you have mono-shock suspension, install the linkage and tighten to the torque recommended by the manufacturer. When re-installing the wheel, double check that the brake, brake calliper mount and spacers are all correctly installed.
Adjust chain tension
You are nearly finished: Adjust the chain tension as explained above in these instructions so that the wheels are perfectly aligned, and then tighten the swing arm and wheel axle and the sprocket with a torque wrench in accordance with the manufacturer specifications. Secure the rear axle nut with a new cotter pin if necessary. Once you have re-installed the cover, the gearshift and the chain guard, check all the fastenings once again. After approx. 300 km, you should check the tension of your chain again – new chains tend to stretch initially. And don't forget to lubricate – if you use your bike for touring, or simply do lots of miles, you can effectively prolong the life of your chain kit by using an automatic chain oiler, as well as saving yourself a lot of work.
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The Louis Technical Centre
Problems getting spare parts? Or maybe you've got a technical question about your motorcycle or an accessory The Louis Technical Centre can help! Remember to quote all the necessary details of your vehicle – better still, send us a copy of your registration document.
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These tips for DIY mechanics contain general recommendations that may not apply to all vehicles or all individual components. As local conditions may vary considerably, we are unable to guarantee the correctness of information in these tips for DIY mechanics.
Thank you for your understanding.
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