How do you change a compression spring

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Changing the compression spring step 1

Changing the compression spring or contrast spring is a pretty simple process although for the first time doer it can be a little frustrating and take longer than usual. Don’t let this put you off though as once you’ve done it a few times it becomes easy enough.

You need to start by removing the crankcase cover (this is the cover on the left hand side of the engine where your kick-start is). To do this remove the bolts around the perimeter that holds it in place.

Changing the compression spring step 2

Once you have removed the cover you will be able to see your transmission, you need to be working on the clutch / torque driver etc to the right hand side near the rear wheel.

Changing the compression spring step 3

First of all you need to undo the nut that holds it all in place, in order to do that you need either a clutch holding tool or an impact gun, we opted for the clutch holding tool.

Changing the compression spring step 4

Once you have removed the nut slide the clutch bell off the primary shaft and the clutch and torque driver assembly will be visible, you can now slide the clutch assembly off.

Changing the compression spring step 5

Now you have the clutch assembly in your hand you should be able to see the large nut which holds the clutch onto the torque driver, this is usually around a 34 – 41mm hex on 50cc models. If you are using a clutch tool or large spanner the easiest way to remove the nut is to place your tool over the hex nut and put your palm over it to keep it in place.

Changing the compression spring step 6

With the assembly on its side hit the end of the spanner on a bench or on the floor to shock the nut until it cracks loose, remembering that the thread rotation to release the nut is anti-clockwise.

Now you need to put the clutch assembly flat on a bench and hold the clutch down whilst you undo the nut, remember the spring inside is compressed.

Changing the compression spring step 7

Once the nut is removed you can gently release the clutch allowing the contrast spring to open fully and release the pressure.

Changing the compression spring step 8

You will now have the clutch off and ready to change the compression spring. Simply remove the old spring and replace it with the new one.

Once you have the new spring in place you can reverse the removal process to put it all back together. You might need an extra pair of hands to help you compress the contrast spring down with the clutch whilst you tighten the nut. If you are doing the work on your own a useful way of holding the clutch down is to use your feet. Providing you have the nut nice and tight you are ready to re install it on the scooter by reversing the removal process.