Hi ihave a 2003 honda crf 450 r rebilt the water pump last year worked for two rides started leaking again just put new seal in it again leaking even more at my wits in pleas help

Bent water pump shaft or water seal has been damage putting it in

crf honda's run titanium valves which wear out very quickly if valve clearances not checked very regularly. what happens is the valve wears on its sealing face and clearances close up and then valve rides and looses compression,much like a leaking tap. bike will make more compression and valves will try to seal when warm. i probably rebuild one of these bikes a week with this problem. get it to your dealer and have clearances done. you can get stainless steel valve conversion kits which are much cheaper than honda titanium valves.

yes sir the seal hole should not be oblong, was the bearing bad when you took it out? sounds like the shaft has worn out the hole.

You may have put the seals in backwards. They must go in a specific direction. If that is ok, is the water on the right side oil, or left side oil? Right side you have a seal problem, Left side you have a head gasket. The cylinder wont crack unless destroyed. Replace head gasket and the bad oil on bad side. Chaz Moto DC

Not, sounds like a seal vent for the water pump, shouldn't leak.

Water pump oil seal is not a possible cause. Even if the water and oil seal were so worn out that the coolant passed through both seals the weep hole in the crankcase cover would have to be completely stopped up and sealed. In that case it would leak into the transmission oil not the engine oil. The coolant leak would likely be in the cylinder/head area.

HI,,, YOUR WATER PUMP DRIVE SHAFT HAS WARN A GROOVE WHERE THE WATER PUMP OIL SEAL SITS....SO YOU NEED A NEW WATER PUMP SHAFT GASKETS AND SEALS..MAYBE NEW SHAFT BEARINGS...$100-180 TO GET FIXED..THE WATER NECK FROM YOUR CYLINDER HEAD NEEDS A NEW O'RING.. SIMPLE FIX UP

It means your water pump seal is seeping at this point. Eminent failureportended. Replace water pump. Seals on pumps usually fail because of bearing wear, so this is a precursor to pump shaft failure. Good luck