How To Install a Clutch Kit on a 2008 Yamaha YZ85 Dirt Bike

How to Install a Clutch Kit on a 2008 Yamaha YZ85

Why replace the clutch on a 2008 Yamaha YZ85?

The YZ85 is a high-revving 85cc motocross machine used hard for starts, tight woods, and race conditions. Clutch wear shows up as slipping under acceleration, dragging or grabbing, inconsistent lever feel, hard shifts, or a lever that needs more or less travel to engage. In two-stroke motocross riding these symptoms are common when friction plates glaze, steel plates overheat, springs lose free length, or the basket and hub develop notches. Replacing the clutch kit restores throttle response, power transfer and crisp shift quality.

Clutch system overview what the 2008 YZ85 uses

The 2008 Yamaha YZ85 uses a wet, multi-plate, cable-operated clutch. That means you'll deal with a clutch cable and a stack of alternating friction and steel drive plates inside a wet sump. Proper cable adjustment and smooth cable routing are important because cable stretch or binding can mimic clutch wear by preventing full engagement or disengagement.

Tools & prep

• Basic metric hand tools, a clutch holding tool or impact driver for the center nut, clean rags, drain pan
• New clutch kit (friction plates, steel plates, springs, pressure plate if included), fresh engine oil compatible with wet clutches
• Optional: dial gauge or straightedge for checking plate flatness, spring tester or caliper for free length

Preparing the bike

Park the YZ85 on a level stand, warm the engine briefly to thin the oil, then drain the engine oil into a pan if your clutch cover doubles as an oil cover. Clean around the clutch cover to stop debris falling in when you open it. Disconnect the clutch cable at the lever to give slack before you remove the cover.

Removing the clutch cover and components

• Remove the clutch cover bolts and take the cover off carefully some oil will drain if you didn't fully drain the case.
• With the cover off, note the position of the pressure plate and springs. Remove the clutch springs in a crisscross pattern a few turns at a time to relieve load evenly.
• Take off the pressure plate and then slide out the friction and steel plates one by one, keeping their order. Count them as you remove them so you can compare to the new kit.

Inspection basket, hub, plates, springs and associated parts

Inspect each component carefully:

• Friction plates look for glazing, burned or thinned material and uneven wear. If the friction surface is glassy or significantly undersized compared to the replacement set, change them.
• Steel drive plates check for heat discoloration, warping, or grooving. Warped steels will stack unevenly and cause chatter.
• Clutch basket examine the fingers where the plates contact for notching or burrs. Light burrs can be dressed, but deep notches cause poor engagement and should lead to replacing the basket.
• Clutch hub and inner splines check for wear, sharp grooves or rounded splines that let plates slip on the hub.
• Springs compare free length to the new springs; weak springs compress too easily and cause slipping under load.
• Thrust washer and pushrod confirm smooth surfaces and no excessive play or scoring where the pushrod bears.

Soaking new plates & preparatory steps

Because the YZ85 clutch is wet, soak new friction plates in the same oil you will use for the bike for at least 15-30 minutes. This reduces initial break-in slip and prevents premature glazing. Lightly oil steel plates and any mating surfaces; ensure the clutch basket and hub are clean and free of debris before reassembly.

Installing the clutch kit

• Reinstall plates in the correct alternating order friction, steel, friction, steel matching the count you removed. Ensure each plate seats fully and the tabs align with the basket grooves.
• Once the plate stack is in place, fit the pressure plate squarely over the stack. Start clutch spring bolts by hand in a diagonal pattern to distribute load evenly, then tighten them progressively until snug. Do not torque to a specified value here tighten evenly until the springs are seated and the pressure plate is flush.
• Install any thrust washers or retaining clips exactly where they came from and check the pushrod moves freely when the lever is pulled.

Reassembly cover, oil, cable adjustment

• Clean the mating surfaces of the clutch cover and install the cover. Replace the gasket if required or use a fresh gasket maker as appropriate.
• Refill the engine with the correct capacity and type of oil for wet clutches. Use fresh oil to avoid contamination that accelerates wear.
• Reconnect the clutch cable at the lever. Adjust free play at the lever so there is a small amount of free play before engagement check for smooth travel and no binding through the full throw. Because the YZ85 is cable-operated, correct cable routing and lubrication are crucial; a stuck or rusty cable can mimic a failing clutch.

Bleeding or checking hydraulic components (if applicable)

Although the 2008 YZ85 uses a cable clutch, if you encounter hydraulic conversions or aftermarket systems, check for consistent lever feel and leaks at the slave cylinder. Air will make engagement feel spongy, so address any trapped air before finalizing the job.

Break-in and verification ride

After installation, let the engine idle and operate the clutch lever several times to seat components. Take the bike for a controlled rideuse progressive throttle and avoid repeated heavy launches for the first tank. Verify clean engagement, no slipping under acceleration, and smooth shifts through the gearbox. Recheck cable free play and clutch cover bolts after the initial heat cycle.

When to replace additional parts

If the basket shows deep notching, the hub splines are damaged, or the pushrod/thrust surfaces are rough, replace those parts with the clutch kit or buy them separately. Springs should be replaced with each kit if they show reduced free length or uneven compressionweak springs undermine any new friction plates.

Riding context what wears this clutch fastest?

The YZ85's small-displacement, high-rpm character and motocross use make it vulnerable to clutch wear from aggressive starts, frequent slipping in technical sections, sand, and high-heat racing. Regular oil changes with the right wet-clutch oil and prompt cable maintenance extend clutch life and preserve performance.

Final notes

Installing a clutch kit on a 2008 Yamaha YZ85 is straightforward for a rider with basic to intermediate mechanical skills. Take your time inspecting mating components, soak the friction plates, reassemble carefully, and fine-tune the cable. The result is restored throttle response, reliable power transfer and smooth shiftingexactly what you need to charge the next race or trail session with confidence.

Related Shopping Categories

Shop Clutch Kits for a 2008 YAMAHA YZ85 Dirt Bike.

Shop Clutch Baskets for a 2008 YAMAHA YZ85 Dirt Bike.

Shop Clutch Springs for a 2008 YAMAHA YZ85 Dirt Bike.

Shop Inner Hubs and Pressure Plates for a 2008 YAMAHA YZ85 Dirt Bike.

Shop Clutch Covers for a 2008 YAMAHA YZ85 Dirt Bike.

Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.