Adjusting the tension is bit involved, but is something that needs to be done every once in a while or after replacing the rear wheel. Consult your owner’s manual for the exact amount of chain slack you need. I was working on my 2006 Suzuki GZ250 which needs between 5 and 15 millimeters of chain slack. A chain that is too tight can damage the sprockets or break at the worst possible time. A chain that is too loose might slip off and end your ride.
1. Start by getting all the equipment you will need
You will need:
- a torque wrench
— a 12mm wrench
— a 17mm wrench
— a 19mm wrench
— a 19mm socket
— a hex key (I used a 5mm)
— a tape measure (or some form of measurement)
2. First, check your chain slack to see if it needs to be adjusted. If the slack is within specifications do not bother adjusting it.
You want to measure the distance from the top of the chain, when it is pushed down lightly, to the top of the chain, when it is pushed up lightly.
Take your measurements from about the middle of the chain, halfway between the rear axle and the front sprocket. Until you get used to visually identifying the amount of chain slack your motorcycle needs, use a tape measure to exactly measure the amount of slack there is. The wear on a motorcycle chain is going to be uneven. Therefore, the amount of chain slack will be different on different sections of the chain. You want to take your measurements at the spot where there is the least amount of slack. Turn the wheel and check the slack until you find the spot on the chain that has the least amount.
3. Using your 19mm wrench, loosen the rear axle nut.
This will take a little bit of elbow grease
You do not need to take the nut off. All you need to do is loosen it a couple of turns so the axle is free to move backwards and forwards.
4. Turn the chain adjuster nuts using the 12mm wrench to adjust the chain slack. To tighten, turn the nut clockwise. To loosen, turn the nut counter-clockwise. Inside the swingarm is a little metal block that the axle goes through which pulls the axle back or, when the adjuster nuts are loosened, allows the wheel to be pushed forward to create more chain slack.
Use quarter turns to be safe
Remember, there are two chain adjuster nuts. One on the left and one on the right. They need to be adjusted equally in order to make sure the wheel stays in alignment. Use quarter turns, alternating between each side in order to help ensure the wheel does not go out of alignment.