Water Pump Issues KX65. Help Please

A buddy of mine is having problems with his sons KX65. The kids were just about to go out on the track and I noticed that there was a strange looking fluid in the oil level inspection window on the side of the transmission. After some investigation, we found the water pump to be leaking into the transmission (the rad was empty and the tranny was full of the rad contents). On the KX, the water pump is right in front of the transmission case (see picture below). The first thought was that the water pump wasn't sealing right, so he changed the seals and the problem still persists. Does anyone have any suggestions?



Did he check the shaft to see if it was grooved? Our 2002 KX65 seals were leaking and I ended up replacing the shaft to get it to quit leaking. Also check the bearing.

Depending on the wear - you need the 2 seals and the shaft/plastic gear assembly.

You HAVE to remove the case cover and water pump cover and impeller to remove the seals - orient them properly when putting the new ones in.

Common problem on teh KX65 - done ours twice in less that 2 seasons racing but then he does put well over 140-180 hours on the bike in a season.

Ok, I just did this on my sons bike. At first all I did was change the seals (didnt work for long) so then I changed the bearing, 2 seals and the impella shaft, problem solved.

On your diagram the parts are

1. 13234

2. 92045

3. 92049B

4. 92049A

Good luck, let us know how you go... on a side note check the case hasnt got a hair line crack.

I have the same issue - a strange looking fluid in the transmission oil viewing window. However, the radiator is full?? Is another way for H20 to get in?

yes there are....using a pressure washer too close to the filler cap or kickstarter shaft or clutch actuator shaft can introduce water into it. it only takes a little to go milky. best thing to do is to keep an eye on it, once the rad level drops a little you know it's time, until then, just change the oil frequently - a little moisture isn't a big deal - it won't stop the oil from doing it's job, a lot is a problem though.

Thanks for the response. I do use a powerwasher and thought that might be another reason.

So here is the $100 question - the KX65 always has had oil in it. However, the lower gearbox starting making a high-pitched whining sound at the track last week (sounds like there is gravel in the gearbox!). In addition, the bike has now become hard to start.

I don't think my water in the oil issue caused any harm but I do recognize there is definitely a problem in the motor.

Do you guys think that the bottom end is bad and since it is now hard to start the top-end was somehow affected as well? I am not a wrench /motorhead and have never torn apart a two-stroke motor so anyone's help is greatly appreciated.


If water was in the transmission and it's affected your top end, you've got more than just a bad water pump seal. Does your bike smoke excessively and the transmission fluid mysteriously disappear? If so, you've got a crank seal that's also gone bad.

I'd venture to guess that it's a coincidence.

However, your bike does have some serious issues, time to get out the wrenches.

I'd say it's time to start tearing it down.

The noises/symptoms you're describing are NOT natural and definitely point to a problem.

Like smac said - if your tranny fluid is disappearing you've likely got a bad crank seal - however, if you've got full tranny fluid and those sounds, it may be that something internal let go and is being eaten by your moving parts right now.....not good.

As you tear it down, you will soon see where the problem is, plus, you can inspect your water pump seals....if the shaft is scored in rings - you've probably got a leak and should replace EVERYTHING (shaft, 2 seals and the bearing) or it won't last more than a month.

Thanks guys - I am tearing the motor apart this weekend. Should be fun!

Pulled my cover to replace the clutch and noticed that the washer on the impeller bolt was on the outside, not the backside of the impeller. Which is correct. Want to go back together correctly. Also what is the torque settings on the clutch hub and side cover bolts.

washer goes BEHIND impeller.

Side cover bolts - 78 in/lbs (includes all on water pump cover incl. drain)

Clutch hub - 47 ft/lbs

6 bolts on Clutch wheel - 82 in/lbs

Thanks, I should also use blue locktitie on all fasteners- correct? also should

I put the gaskets on dry?.

Gaskets dry is fine

I like your spelling of locktite but even with that spelling, no matter how tempting it may be, keep your hands off it.

Torquing it properly (working your way up to final torque in 1/3rd increment stages on all fasteners in a star fashion) is all that is required. torquing fasteners covered with locktite, anti seize or grease is never recommended since it can drastically affect the actual torque value you will end up with and result in snapped fasteners and all sorts of other trouble, fasteners should always be as clean as possible when being torqued.

Also - please note that the torque values I supplied you vary between ft/lbs and in/lbs, there are 12 in/lbs in one ft/lbs so make sure you're not overtightening!

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