Clutch Tips

The Clutch

The clutch inside your dirt bike has a very important role: which can affect handling and power delivery. Traction will be lost if the clutch doesn’t engage and disengage smoothly. A few questions to ask yourself about your clutch: Does your clutch plates burn out fast? Does you clutch make any grinding noises while idling in neutral? Does your bike still try to creep forward while the in neutral? Is clutch operation smooth (able to control power delivery) or like a light switch on and off? These questions can help identify your clutch problems so the issue can be resolved.

Clutch Tips

Most people just replace the clutch springs but if you want to maximize the life of the clutch springs (and your money) you will need to measure their free length. Calipers will be needed to measure the spring’s free length and you’ll find the specs for the springs in the proper service manual. Once the springs become sacked out and become shorter the clutch will start to slip and the clutch plates can become glazed (burned clutch plates).

There are two kinds of clutch plates: drive plates and fiber plates. The drive plates are made of steel or aluminum and go in between the fibers plates. Fibers plates can be identified by fiber type pads bonded to the plates and the tabs on the outside diameter. These clutch plates can be measure to check their thickness with the same calipers you used to check the springs. Clutch plates can warp is they become overheated. You’ll need a flat surface (piece of glass) to lay the plates on. While applying light even pressure on the clutch plate try to insert a 0.020-in feeler gauge between the flat surface and the clutch plate. If the feeler gauge can be inserted under the plate, the plate is warped and must not be reused.

You may hear a grinding noise coming from your bike while it’s idling in neutral. If so, apply light throttle (just off idle) slightly pull in the clutch lever. Check for a reductions in the grinding noise or even vibration. If the noise is reduced then check for a worn needle bearing and sleeve that fits in between the main transmission shaft and clutch basket. If the noise isn’t affected by clutch engaging then the problem could be more serious. The entire clutch side components will need to be inspected. If your bike creeps forward while in neutral then you could have notches worn into the clutch basket fingers and or inner clutch hub. Once the notch marks become too deep the clutch plates stick in one place and don’t engage or disengage properly. Some people have repaired notch marks with draw files but if you’re unsure how to properly perform that task your better off by replacing the clutch basket and inner hub. These tips don’t replace the factory service manual or the skills of a trained professional.