How to Rebuild and Replace Yamaha YFZ450R Clutch

This walkthrough will show you how to change the clutch plates in your Yamaha YFZ450R and also replace the entire clutch assembly. 

Watch the clutch replacement video above so you're fully up to speed on how to disassemble and rebuild a Yamaha YFZ450R clutch. We also recommend you purchase a complete clutch plate kit, as it is cheaper than buying the clutch plates individually. The Yamaha clutch plate kit includes new clutch springs and a clutch cover gasket. If your clutch is badly worn, you'll also need to replace the clutch assembly itself. 

Yamaha YFZ450R ATV

See the OEM Yamaha clutch parts diagram for reference. Note that if you're replacing the clutch assembly, you must get a clutch holder tool to disassemble and reassemble it.

Tools and Parts Needed - YFZ450R Clutch Rebuild

Tools

  • Flatblade screwdriver
  • Pick tool
  • 8mm, 10mm,12mm, 30mm sockets

 

  • 3/8th ratchet
  • Torque wrench
  • Clutch boss holder

Parts:

Clutch Plate Replacement

  • Clutch plate kit

           or

  • Inner/outer friction plates (x2)
  • Central friction plates (x6)
  • Drive Plates (x7)

Parts:

Clutch Assembly Replacement

  • Primary driven gear
  • Clutch boss
  • Thrust washer
  • Lock washer
  • Clutch springs (x6)
  • Clutch cover gasket

Yamaha YFZ450 clutch plate kit

How to Disassemble Yamaha YFZ450R Clutch

Step 1. Soak the new clutch friction plates in engine oil for an hour before installing them.

NOTE: The Yamaha YFZ450R uses two different types of clutch friction plate, each of which has its own part number. You may wish to soak the different plates separately. If you mix them together, the two outer friction plates are darker than the other plates, so you can tell them apart.

Step 2. Remove the two oil drain bolts. One is located under the engine to the front, and the other is located on the left side of the engine below the shifter pedal. Once the oil has completely drained, reinstall the bolts and torque them to 14 foot-pounds.

Step 3. Remove the clutch cover. The cover bolts are different sizes, so make a note of which bolt goes where for when it's time to reinstall them.

Yamaha YFZ450 clutch cover removal

Step 4. Remove the clutch spring bolts. Back the bolts off a few turns at a time and work in a diagonal pattern to maintain even pressure on the pressure plate and prevent it from getting damaged.

Yamaha YFZ450 clutch spring removal

Step 5. Remove the old friction plates and drive plates from the primary driven gear. 

Yamaha YFZ450R clutch plates removal

NOTE: The primary driven gear is commonly referred to as the clutch basket.

Step 6. Inspect the teeth of the clutch basket and the clutch boss for wear. If both are in good condition and only the clutch plates need changing, skip over to the clutch plates replacement section (How to Replace Yamaha YFZ450R Clutch Platesbelow.

Yamaha YFZ450R clutch basket and boss

How to Replace Yamaha YFZ450R Clutch Assembly

Step 1. Remove the central push rod, bend back the tab on the lock washer from the clutch nut, hold the clutch boss with a clutch holder tool, and remove the clutch nut and washer.

Yamaha YFZ450 clutch assembly

Step 2. Remove the old clutch boss, the thrust washer behind it and the clutch basket.

Step 3. Remove all of the old clutch cover gasket from the clutch housing and the clutch cover. Be careful not to let any fragments of the old gasket get into the clutch housing.

Step 4. Put a smear of oil on the new clutch basket's central bearing and install it into the clutch housing.

NOTE: You may have to rotate the gear sprocket behind the clutch basket to get the basket to engage with the gear sprocket's teeth. Only when they are engaged will the clutch basket seat properly in the clutch housing.

Yamaha YFZ450R clutch basket

Step 5. Install the thrust washer and the new clutch boss.

PRO TIP: You don't have to replace the old thrust washer, but a new one is cheap, so you might as well install a new thrust washer while the clutch is disassembled.

Step 6. Install a new lock washer and replace the clutch nut. Hold the clutch boss with the clutch holder tool and torque the clutch nut to 54 foot-pounds. Bend the lock washer tab against the nut to secure it. Reinstall the central push pin.

Yamaha YFZ450R clutch boss holder tool

How to Replace Yamaha YFZ450R Clutch Plates

Step 1. Install the new clutch plates in the following order. 

1. Inner/outer friction plate (Yamaha part # 5TA-16321-00-00)

2. Metal drive plate (Yamaha part # 4X7-16325-00-00)

3. Central friction plate (Yamaha part # 5VY-16321-00-00)

4. Metal drive plate (Yamaha part # 4X7-16325-00-00)

5. Central friction plate (Yamaha part # 5VY-16321-00-00)

6. Metal drive plate (Yamaha part # 4X7-16325-00-00)

7. Central friction plate (Yamaha part # 5VY-16321-00-00)

8. Metal drive plate (Yamaha part # 4X7-16325-00-00)

9. Central friction plate (Yamaha part # 5VY-16321-00-00)

10. Metal drive plate (Yamaha part # 4X7-16325-00-00)

11. Central friction plate (Yamaha part # 5VY-16321-00-00)

12. Metal drive plate (Yamaha part # 4X7-16325-00-00)

13. Central friction plate (Yamaha part # 5VY-16321-00-00)

14. Metal drive plate (Yamaha part # 4X7-16325-00-00)

15. Central friction plate (Yamaha part # 5VY-16321-00-00)

16. Inner/outer friction plate (Yamaha part # 5TA-16321-00-00)

NOTE: If you mixed the two types of friction plates together while soaking them in oil, the two inner/outer friction plates are slightly darker in color than the six central friction plates.

Yamaha YFZ450 clutch rebuild assembly

How to Rebuild Yamaha YFZ450R Clutch

Step 1. Reinstall the pressure plate, the clutch springs and clutch spring bolts. The clutch plate kit includes new clutch springs. If you didn't get the kit, the old springs should measure 47.8mm and will need replacing if they measure any less.  

Yamaha ATV clutch rebuild

Step 2. Tighten the clutch spring bolts a few turns at a time, and work in a diagonal pattern to keep the pressure even across the pressure plate so as not to damage it. Once the spring bolts bottom out, torque them to 7.2 foot-pounds.

Step 3. Install a new clutch cover gasket and reinstall the cover. Torque the cover bolts to 7.2 foot-pounds.

Yamaha clutch cover replacement

Step 4. Refill the engine with Yamalube motor oil and you're done.

Yamaha YFZ450R ATV clutch rebuild

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