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Water Pump & Balancer Shaft Rebuild


GhostFace

2006 Honda CRF450R

WATER PUMP LEAKAGE AND BALANCER SHAFT BEARING SERVICE.

PLEASE READ IN FULL BEFORE STARTING.

I AM NOT RESPONSIBLE FOR YOU TRASHING YOUR ENGINE; THIS IS JUST THE WAY I DID IT.

When I got my 2006 CRF450R the water pump was leaking coolant out of the weep hole underneath. I was aware of this as the previous owner has done the seal twice before but hadn’t solved the problem. I assumed it was the water pump bearing worn out, making the water pump shaft vibrate and blow the seal. Upon closer inspection I discovered the balancer shaft which drives the water pump was moving about on its bearing, thus calling for bearing replacement. I’m a bit of a novice mechanic but fancied having a go because I hate paying shop labour prices, this is a step by step guide to what I’ve done to replace my balancer shaft bearings and stop the leak once and for all.

1. Drain the coolant via the drain bolt at the base of the water pump cover.

2. Drain the transmission oil.

3. Remove the rear brake pedal and kick start.

4. Remove radiator hose at the top of the water pump cover.

5. Remove water pump cover.

6. Remove the complete right side casing, including the clutch cover.

7. You now have a casing in your hand with the water pump shaft, impeller, two seals and the bearing still in place.

Now to service the water pump, gently hold the rear of the shaft with a pair of grips and remove the impeller with an 8mm socket, remove the impeller and the small washer. Now would be an ideal time to do the impeller modification if your bike is 05 or older, another story. Remove the water pump shaft and inspect for ware, any groves in the shaft, then replace it. Seal removal and bearing removal is a fine art and there are lots of ways to do it, I will just say how I did it but it’s up to you to do it your way. I removed the front seal by gently tapping from the rear with a flat blade screw driver, the rear seal sits behind the bearing so I made an improvised bearing puller using a bolt, 2 nuts and a washer behind the seal with pulled out the bearing and seal together. To reassembly, the seals go in first, with the recessed side facing away from the casing, then the bearing, presses in the same way as removal but obviously reversed, lightly grease the inner lips of the seal before inserting the shaft to stop friction burn on initial fire up, mine came ready greased from Honda. Then re-fit the impeller onto the shaft, not forgetting the little washer. The waster pump is now rebuilt and the casing could be fitted back onto the engine, not forgetting the new gasket. I also did the kick start shaft seal as it was easy and cheap to do.

Now is the time to decide if you need to replace your balancer shaft bearings, you will see your clutch and two gears side by side, the one nearest the front of the engine is attached to the balancer shaft, if you hold the balancer gear and move it in a circular motion looking for free play up and down, side to side. Any movement is wear, with new bearings it will not move at all. If you have any ware, replace them now as you will have wasted your time doing the water pump.

Drain your engine oil, remove the left side engine casing, at the front of the engine you will see the other side of the balance shaft above the nylon gear that drives the oil pump, chances are that the left side bearing will be ok but I done mine anyway because I’m not tempting fate one I have it apart.

This bit is very important, the balance shaft and gears are designed to stop the engine shaking itself to bits due to single cylinder vibration, the gears on the end of the shaft are weighted on one side, these need to go back into the same position that that were removed from or the whole thing will be out of balance. I dried the oil of the gear on each side and marked the tooth with the corresponding one on the gear next to it, or the nylon gear for the left side, I used simple white stationary correction fluid.

If you are going to do the balance shaft bearings, put them in the freezer now so later they will be slightly smaller and easier to insert later.

To remove the balance shaft first you need to remove the weird shaped nut on the right end of the shaft, I had a special socket made but it didn’t arrive in time so I simply tapped it around with a flat screwdriver and hammer, I didn’t even need to lock the gear, remove the balance gear and washer, now pull the shaft out from the left side, the shaft sits in an enclosed tunnel and nothing will fall into the engine casings.

You now have a hole right through the front of your engine, on the right side, remove the two bolts and fixing plates, I removed the bearing by gentle tapping with a long large screw driver inserted from the left side. The right side has an oil seal, a circlip then the bearing, gently prise out the oil seal with a flat screw driver and remove the circlip, I removed the left side bearing by hitting with a socket on an extension bar inserted from the right side, you can only get to about 2/3rds of the bearing so be wise with your choice of socket.

Remember, if like me you attempt this with your bike on a jack up stand you will get nowhere as the force is transferred into moving the bike off the stand, I leaned mine against a wall, leaning on the handle bar.

Remove the bearings from the freezer and drive them into place with a relevant sized socket and large hammer (at own risk), roller on the left and race bearing on the right, replace the circlip and then the oil seal on the right and the two plates and bolt on the left. Now insert the balance shaft from the left side, and align the teeth with the corresponding white markings on the nylon gear, Get some one to hold the gear in place because it is weighted and will rotate out of line if you let it.

On the right side align the balance gear with the white markings on the gear next to it and push into place, refit the washer and weird shaped nut. Refit casings, rear brake and kick start, oil and coolant.

Remember, I will not be held responsible for anything that goes wrong, this is just the way I did it.

The parts I used were:

Left and right engine casing casket.

Kick start shaft oil seal.

Water pump oil seal.

Water pump water seal.

Water pump bearing.

Balancer shaft oil seal.

Balancer shaft race bearing.

Balancer Shaft roller bearing.

Have a beer, job done.


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