Changing the chain and sprocket kit

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.

Changing the chain and sprocket kit

Changing the chain and sprocket kit on motorcycle

Continuous improvement in manufacturing technologies means that modern O, X and Z-ring chain kits offer outstanding mileage – but the drive components are still subject to constant wear and tear.

“Wonky teeth” on the sprocket and chain wheel and ever-decreasing retensioning intervals are a sign that a new chain and sprocket kit is required! But generally, replacement tends to be long overdue. 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 set – because they know that a new chain will very quickly adjust 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. 

A drive chain is only as strong as its weakest link. If the chain is mounted with a rivet link, make sure the riveting is carried out carefully and professionally using a suitable chain tool.

Important: 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. Chain screw locks are available specially for Enuma chains and must be mounted precisely as described in the accompanying instructions.


Changing the chain and sprocket kit – now let's get started

Step 1 – Undo sprocket

Step 1: Undo sprocket

01 – Undo sprocket

To get at the chain sprocket, you may 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. 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 wrench nut and a spot of elbow grease.


Step 2 – Removing the rear wheel

Step 2: Removing the rear wheel

02 – Removing the rear wheel

Now remove the rear wheel. If you don't have a centre stand, please bear in mind that a jack which is attached at the swing arm is not suitable for removing the swing arm. 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. 

Please note: Make a note of the mounting location of the spacer sleeves!


Step 3 – Replace chain wheel

Step 3: Replace chain wheel

03 – Replace chain wheel

Unscrew the chain wheel from the sprocket mount on the rear wheel. Here too, bend open any tab washers beforehand. You should always fit new tab washers or 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 rear-wheel damper behind the sprocket mount still correctly tensioned? Replace any damaged components.


Step 4, Fig. 1 – Remove linkage and ...

Step 4, Fig. 1: Remove linkage and ...

04 – Remove swing arm

The swing arm has to be removed to fit an endless chain. This is not necessary if you are using a connecting link and you can continue with Step 07. The swing arm is removed as follows: 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. 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.

Step 4, Fig. 2 – ... Remove swing arm.

Step 4, Fig. 2: ... Remove swing arm.

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 hub 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.


Step 5 – Install new chain sprocket

Step 5: Install new chain sprocket

05 – Install new 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 reinstall it correctly to ensure the correct chain alignment. An incorrectly aligned chain may break! Please note: 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. These will be tightened later with a torque wrench.


Step 6 – Clean, grease and re-assemble

Step 6: Clean, grease and re-assemble

06 –  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. If you removed 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.


07 – Chain with connecting link

If the chain is mounted with a connecting link, refer to the enclosed installation instructions or instructions for using the chain tool.


Step 8, Fig. 1 – Play at lower chain run

Step 8, Fig. 1: Play at lower chain run

08 – Adjust chain tension

Nearly finished: Adjust the chain tension/slack as follows: 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 at 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 chain alignment tester, long straight batten or a piece of string. 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! The Chain Monkey can come in handy when tensioning the chain.

Step 8, Fig. 2 – Adjust chain tension

Step 8, Fig. 2: Adjust chain tension

Then tighten the swing arm, wheel axle and sprocket with the torque wrench according to the manufacturer’s specifications. Secure the rear axle nut with a new cotter pin, if applicable. Once you have reinstalled the cover, gearshift and chain guard etc., 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 do not forget to lubricate! Those who use their bike for touring or simply do lots of miles can extend the life of their chain kit and also avoid a great deal of work at the same time by using an automatic chain oiler see Tip Chain lubrication system and Tip Chain maintenance.


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Please note!

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.