4. Adjust for proper belt-to-sheave clearance
Belt-to-sheave clearance is the amount of side-to-side free play that the belt has in the primary clutch. If this free play is excessive, the machine can experience a number of negative side effects such as an overly abrupt engagement, an engagement bog, a low speed hesitation and even premature or excessive belt and clutch wear.
To prevent these effects, check and adjust the free play so that the belt has .010-.020 inches clearance between it and the clutch. It is best to take this measurement using a new belt and get the clearance as close to .010 inches as possible to allow for belt wear. To get an accurate measurement, pull the belt tight around the center shaft of the primary clutch while sliding it to one side against the sheave so that the gap is all on one side of the belt. Use a feeler gauge to measure the open gap between the belt and the clutch sheave. If the clearance is not within the specification, the spider will need to be disassembled to allow access to the shims that will need to be added or removed to correct the issue. Consult the service manual for spider removal procedure or contact a performance shop or dealer that offers this service.
5. Maintaining wear items can save you time and money in the long run
The belt is the easiest wear item to replace and often needs it soon before it fails. A worn belt can cause a significant loss in performance, yet we often forget to install a new belt as our first troubleshooting test, costing us time and even money if a destroyed belt damages other parts. The belts that are being used on new, high horsepower machines are so strong that they will wear to the point of poor performance yet not de-laminate or fray for some time after.
Other wear items often overlooked are bushings. All bushings including cam arm (primary weight), cap, sheave and helix bushings should be replaced when the free play gets close to or exceeds its allowable amount. These specifications can be obtained from the proper repair manual or your local dealer. If these types of serviceable parts are ignored, the wear will reach the point of eating away at the actual clutch, making the entire clutch non-serviceable and in need of total replacement. A $5 weight bushing is much easier and cheaper to replace than an entire $400 to $1,200 clutch assembly.
Fuel economy is also reduced when clutches aren't working to their full potential. To achieve the best fuel economy, all parts need to be in good shape, and if they are not, horsepower will be wasted trying to make the worn part do its job. Any time horsepower is wasted, fuel economy is reduced and cost of operation is increased.
6. Use the specific belt recommended for your clutch setup
