top of page

Transmission change on your chipper.



On this tutorial, we will cover how to make a complete transmission swap on your chipper. The model utilized here is the chipper shredder 2090, but the concept is pretty much the same on all of our chippers. This tutorial serves well if you need to change the clutch, the pulleys or the belts. 

Step 1.




First off, tools needed. We will use:


7/16" | 1/2" | 9/16" | 3/4" hex wrench (one of each).

1- Pulley extractor (optional, but handy).

1- Long straight edge (make it at least one foot long).

1- hammer or rubber mullet

1- a piece of hardwood

tools needed for chipper transmission change

Step 2.


What you'll need


1- Pulley with 1" tapered hub with 1/4" key

1- Clutch with key.

1- Hex Bolt 3/8" x 1-1/2" NF grade 5. (black)

1- Hex Bolt 3/8" x 1" NC grade 5

2- 3/8" Flat washers

2- 5/16" Flat washers

4- 1/4" x 1" hex bolts grade 5 -black colored (2 are additional in case you need to realign pulley)

pulley, clutch and fasteners for chipper transmission

Step 4.


Now grab the 3/8 x 1-1/2" Bolt and assemble with a 5/16" flat washer first, and then with a 3/8" flat washer and apply a dab of threadlocker to secure the fastener.

apply threadlocker to clutch bolt

Step 5.


Screw the setup in place.

clutch bolt assembly on engine shaft

Step 6. 


Tighten with one hand pulling gently on the starting recoil rope and the other with the 9/16" hex wrench in a clockwise manner.


clutch bolt tigthening with hex wrench

Step 7. 


Pulley Assembly


Now onto the rotor shaft. Insert then tapered hub into the pulley. Align the hub unthreaded holes with the pulley holes. Screw in the two bolts and tighten by hand. Do not tighten with tools yet.


chipper rotor pulley with tapered hub assembly

Step 8. 


Slide the the pulley and hub on the rotor shaft. Align keyways and insert key. If needed, hit the key mildly with a hammer. At this point the pulley should still be able to slide by hand, if not we can use a hammer and a piece of wood to correct position. Align by eye with grooves on the clutch.


pulley assembly mounted on chipper rotor shaft

Step 9. 


Belt assembly


Insert the belts. First, make sure that the engine is pushed all the way closest to the rotor shaft. Insert the belts by placing the belt on the clutch grooves first. Then finish off by rotating the pulley and the belt will slip into position by itself. Make sure that your fingers doesn't get pinched between the belts and grooves!


belts mounted on pulley and clutch

Step 10. 


Pull the engine away from the rotor by adjusting the engine bolt in a clockwise manner. Tighten until the belt looks firm. We will apply required belt tension in the next steps.


adding tension to belts

Step 11. 


You will notice that when the engine is being pulled away, it will veer off because of the belt tension that is being applied. To correct, adjust the side bolt in a clockwise manner until the engine is straight.


aligning engine on chipper

Step 12. 


To make sure the engine is straight, measure the length between the engine base face and the face of the chipper base. On each side . Variation allowed to our specs is 1mm or 0.04".


checking engine alignment

Step 13. 


Now place a straight edge that touches the outer face of the pulley. Don't let the straight edge touch the clutch. Measure the gap between the edge and the belt along the length of te edge. To align, the gap must be the same along the length of the edge. At this point to you will correct the gap by moving the pulley in or out.


When the pulley is in the aligned position, make sure to move the pulley another 3/16" further in. The pulley will shift outwards this approx. distance when tightening the center hub.


checking belt alignment

Step 14. 


Now, tighten the pulley tapered hub. It is best to alternate equal small amount of turns on each bolt to allow the tension to kick in and prevent bolt failure.


tightening pulley hub

Step 15. 


To apply correct tension we utilize a belt tension meter. Tension force required is 8lbf.


checking belt tension on chipper

Step 16. 


If you don't have such a tool, rule of thumb is to apply tension until the belt does not deflect more than 1/2" ( as shown in pic below).


manually checking belt tension

Step 17. 


Now that the belt is aligned and the belt has correct tension, it is now time to wrap this up.

Tighten the engine bolts.


tightening engine bolts

Step 18. 


Assemble safety fastener onto the rotor shaft. Make sure to slide a 5/16" flat washer first, and then a 3/8" flat washer. Apply threadlocker and screw in rotor shaft.

This step concludes our tutorial on how to change the transmission on your Yardbeast wood chipper.


tightening pulley end bolt
bottom of page