REPAIRING A WATERPUMP
Step-by-step:
1 CLEAN THE ENGINE
Clean the engine and make sure there is no dirt that could fall in when you remove the sidecase. Drain all the coolant out of the cooling system.
2 REMOVE THE PEDAL
Remove the kickstarter, brake pedal and any coolant hoses or oil lines that are attached to the sidecase.
3 SIDECASE OFF
Remove all the bolts holding the sidecase and remove it. Then give it a good clean in a chemical parts washer and remove any old gasket material.
4 REMOVE THE COVER
Remove the waterpump cover from the sidecase and then the waterpump impellor so that the shaft will slide out of the back.
5 KNOCK THE SEALS
Using a punch, knock the old bearing and seals out of the sidecase. Give the casing a good clean and remove any corrosion or dried coolant with a piece of light sandpaper.
6 SPRAY LUBRICANT
Grease the new bearing and seals with a light lubricant such as silicon spray and, using a bearing and seal installer, knock the new bearing and seals into place.
7 GREASE THE SHAFT
Grease the new impellor shaft and gently slide it into place. Refit the impellor to the shaft. Then make sure the impellor spins smoothly without binding before refitting the sidecase.
8 REFIT THE CASE
Refit the sidecase to the engine using new gaskets and pour in new oil and coolant. Refit the kickstarter, brake pedal and anything else that you have removed. Start the bike and let it warm up while checking for any leaks.
TIPS
• The bolt or nut that secures the waterpump impellor often has a left-hand thread.
COOLING YOUR TOOL
• The majority of bikes these days have mechanical water pumps. This means there is a shaft driven by the engine with an impellor on the end of it. This impellor spins and pushes the coolant through the system, taking the heat away from the engine and dissipating it through the radiators.
• The waterpump shaft usually runs in the right-hand sidecase and has a seal to keep the coolant out of the engine oil. Like all seals, this one wears and needs replacing from time to time.
• Usually there is a small hole in the bottom of the sidecase that leaking coolant drips out of, warning you that the seal is leaking. On some bikes, the coolant gets into the engine oil, making it turn a milky colour.
DOs
• Replace any worn parts
• Always use new gaskets
• Use lubricant when fitting new seals and take your time
• Grease the new waterpump bearing and impellor shaft before fitting
DON’Ts
• Fit new seals onto a damaged waterpump shaft
• Reuse old gaskets
• Fit new seals without grease
• Reuse any damaged or worn parts
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