Tech Tips!

by Jonathan Teraji

Let's Talk YSR Clutch!

 Friction Plates

The most important part of the clutch are the friction plates. They take the most wear and tear, not to mention abuse! Friction plates are designed to be an item that is expendable. They are supposed to wear out, as a result they need to be replaced occaisionly. How often, depends on you. If you are racing, we suggest every 3 races. This is due to the need of feathering the clutch to stay up on the power band. If you are doing normal street riding, you can figure once a year. If you are doing abnormal (?) street riding, .i.e., lot's of wheelies, burn outs etc, you can expect to replace the clutch quite frequently.

Friction plate life can be somewhat lengthened by doing a few simple things. First and foremost, use a clutch that is of the highest quality. Be sure all related components are in excellent condition. This means ALL related stuff. Your clutch springs, hub, pressure plate, outer basket, push rods, clutch cable, actuator mechanism, and the lever and perch. The correct amount of oil, and the correct type and viscosity of the oil is a must! Also keeping the oil fresh is a plus. All of these items will affect how well the clutch works and the "feel" of the clutch.

Metal Drive Plate

Proper clutch operation requires all of the clutch components to work well together. The YSR has one metal plate. It must be in good conditon to operate properly. Check it for correct thickness, and flatness. It can have no hot spots or discoloration. If any of these criteria are not correct, replace it!


Weak or fatigued springs are a major area of poor clutch action. Weak springs will cause slippage and premature wear. All four springs must be the same type. Excessively heavy springs can cause problems also, such as, but not limited to, premature accuator failure, excessive stress on case covers etc.

Clutch Specs
Friction Plate Min/Max Thickness 2.7mm-3.5mm
Quantity 2
Metal Plate Thickness 2.0mm
Metal Plate Warpage Limit 0.05mm
Clutch Spring Free Length (Min) 28.2mm
Push Rod Bending Limit 0.2mm
Pressure Plate Screws Torque 4.3 ft/lbs
Clutch Boss Nut Torque 32 ft/lbs
Tranny Oil 600cc (No Synthetics)


The stock from the factory YSR clutch is a barely adequate unit. The springs are way too weak and the friction plates are lacking in a big way. We would strongly suggest replacement with our clutch kit, however, just replacing the clutch is not enough. PROPER ADJUSTMENT is mandatory!

Clutch Adjustment
1. Loosen Cable length adj. locknut 2. Loosen clutch adj lock nut
3. Turn adj until lightly seated 4. Turn out ajdust 1/8 turn
5. Tighten adj. lock nut 6. Adj lever free play (2-3mm)
7. Tighten cable length lock nut 8. Put rest of stuff back on!
9. Go Ride-Have a good time-Be safe!  

 Push Rods

There are two push rods and a ball bearing involved in teh clutch acctuatings process. The push rods tend to get a big dimple in their ends over time. They are inexpensive, and replacement will enhance clutch action.

Clutch Cable

Lube it. Adjust it. Life is good!

Clutch Kit

The Clutch Kit, when properly installed and adjusted, will greatly enhance the delivery of power to the rear wheel. Don't leave home without it!

That's it for this month, shoot me some E-mail if you have specific YSR questions and I'll do my best to answer them as time allows, and/or suggestions for topics in "Tech Tips!" Remember this page is for you!


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