SG250 Chain Adjustment
Chain Adjustment
This section of the Owner’s and Service Manual addresses adjusting the SG250 motorcycle’s chain and aligning the rear wheel.
You don’t have to get the rear wheel off the ground to adjust the SG250’s chain.
Adjusting the chain on a motorcycle consists of two jobs: Adjusting chain tension and aligning the rear wheel.
You can check this adjustment easily, and you should perform this check on a regular basis. A lubricated chain will require adjustment every 500 to 1000 miles once the motorcycle is broken in.
Adjusting the chain involves loosening (but not removing) the rear axle, loosening the adjustor nuts and locknuts, using a screwdriver between the chain and the rear sprocket to remove all kinks, aligning the rear wheel, tightening the rear axle, and tightening the adjustor nuts and locknuts.
You should check the chain adjustment during your motorcycle’s first scheduled maintenance and at every scheduled maintenance thereafter. The biggest adjustment will occur at the first service interval, because chains do most of their stretching in their first several hundred miles of use. When the chain is properly adjusted, it should have about 15mm (or 3/5 of an inch) slack at its midpoint.
Sprocket and Chain Inspection
The SG250 has a 428 chain, a 17-tooth front sprocket, and a 50-tooth rear sprocket. If you keep your chain properly adjusted and lubed, the chain and sprockets will last much longer than they would if you don’t maintain these items, but they still won’t last forever. You can expect the chain and sprockets to wear more quickly if you ride in dusty environments or off road, or if you don’t lube the chain regularly. Chains and sprockets should be replaced as a set. Do not replace one sprocket without replacing the other or rapid wear will result.
Remove the countershaft sprocket cover by removing the bolts that attach it to the engine. You don’t have to remove the gear shift lever to remove the countershaft sprocket cover.
If the sprocket teeth are hooked or otherwise excessively worn, replace both sprockets. If the chain has excessive stretch or if it has kinks that you cannot work out by manually rotating the links with respect to each other, it’s time for a new chain.
The SG250 motorcycle chain does not have a master link. When you need to replace the original equipment chain on your motorcycle, you have to cut it off.
Please call us at (800) 884-4173 to order replacement chains and sprockets.
This section of the Owner’s and Service Manual addresses adjusting the SG250 motorcycle’s chain and aligning the rear wheel.
You don’t have to get the rear wheel off the ground to adjust the SG250’s chain.
Adjusting the chain on a motorcycle consists of two jobs: Adjusting chain tension and aligning the rear wheel.
You can check this adjustment easily, and you should perform this check on a regular basis. A lubricated chain will require adjustment every 500 to 1000 miles once the motorcycle is broken in.
Adjusting the chain involves loosening (but not removing) the rear axle, loosening the adjustor nuts and locknuts, using a screwdriver between the chain and the rear sprocket to remove all kinks, aligning the rear wheel, tightening the rear axle, and tightening the adjustor nuts and locknuts.
You should check the chain adjustment during your motorcycle’s first scheduled maintenance and at every scheduled maintenance thereafter. The biggest adjustment will occur at the first service interval, because chains do most of their stretching in their first several hundred miles of use. When the chain is properly adjusted, it should have about 15mm (or 3/5 of an inch) slack at its midpoint.
| If your chain requires adjustment, loosen the rear axle. The rear axle is loosed by loosening the rear axle bolt and nut. This photo shows the axle nut on the right side of the SG250 motorcycle. |  |
| The left rear axle bolt head. |  |
| The rear axle adjustor nuts and locknuts are located behind the adjustor plate on both sides of the swingarm. Loosen both nuts on both sides of the swingarm. |
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The intent is to position and align the rear wheel such that the chain has 3/5 of an inch slack at its midpoint. This is the amount of slack the chain should have with the motorcycle on the ground and the rider on the bike. If the bike is on a lift such that the rear wheel is off the ground, you should increase the amount of slack when you adjust the chain such that when you are on the bike, the slack is 3/5 of an inch. If the rear wheel must move forward to increase chain slack, back off on the adjustor nuts and locknuts and manually push the rear wheel forward. If the rear wheel must move rearward to decrease chain slack, tighten the inner nuts as required on both sides of the swingarm to move the axle to the rear.
| After moving the rear wheel, put a screwdriver between the chain and the rear wheel sprocket (as shown below) and sharply rotate the rear wheel. This will remove any kinks in the chain. Note that this photo shows the TT250 motorcycle, but the procedure is the same for either the TT250 or the SG250 motorcycle. |
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| Check the alignment of the rear wheel by comparing the scribe marks on the rear axle adjustors with the scribe marks on the swingarm. This photo shows the right side of the motorcycle and the scribe lines. |
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| This photo shows the left side of the motorcycle and the scribe lines. |  |
| You do not need to remove the rear axle to adjust the chain. Just loosen it and use the adjustor nuts to move the wheel to its required location. When the rear wheel is aligned and the chain slack is correct, tighten the rear axle to 35 ft-lb. Tighten the rear axle adjustors’ positioning nuts, and then tighten the rear axle adjustors’ locknuts (the outer nuts) to lock the adjustors in place. Lube the chain every time it is adjusted. You can use either a wax-based or an oil-based chain lube, CSC stocks both types. You can call us at (800) 884-4173 if you need chain lube. |
Sprocket and Chain Inspection
The SG250 has a 428 chain, a 17-tooth front sprocket, and a 50-tooth rear sprocket. If you keep your chain properly adjusted and lubed, the chain and sprockets will last much longer than they would if you don’t maintain these items, but they still won’t last forever. You can expect the chain and sprockets to wear more quickly if you ride in dusty environments or off road, or if you don’t lube the chain regularly. Chains and sprockets should be replaced as a set. Do not replace one sprocket without replacing the other or rapid wear will result.
Remove the countershaft sprocket cover by removing the bolts that attach it to the engine. You don’t have to remove the gear shift lever to remove the countershaft sprocket cover.
If the sprocket teeth are hooked or otherwise excessively worn, replace both sprockets. If the chain has excessive stretch or if it has kinks that you cannot work out by manually rotating the links with respect to each other, it’s time for a new chain.
The SG250 motorcycle chain does not have a master link. When you need to replace the original equipment chain on your motorcycle, you have to cut it off.
Please call us at (800) 884-4173 to order replacement chains and sprockets.