"Milky Oil" in '97 KX 250

[G22inSC]

While riding yesterday I tried to shift from 2nd to 3rd and the bike would not go into 3rd. At the same time, the bike cut-off. I got it back to the house and began to investigate. It was not seized and seems to still have good compression. I started for a second and noticed there seems to be a pronounced rattle. I pulled the clutch and found milky oil and lots of coolant in the bottom end. I checked the coolant level and it is almost empty.

I am assuming from reading here in the past it is probably the seals and/or water pump impellar. Does anyone know what all parts I should replace to solve the waterpump problem. As far as the rattle, do you think it is possible the milky oil fried the bottom end bearings? Thanks for any help.

 

[YZ165]

I am assuming from reading here in the past it is probably the seals and/or water pump impellar. Does anyone know what all parts I should replace to solve the waterpump problem. As far as the rattle, do you think it is possible the milky oil fried the bottom end bearings? Thanks for any help.

Replace both the water pump seals and the water pump shaft. That should solve the water leak/loss problem.

As far as the bottom/top end goes, it could be either, or something in the tranny. Without coolant, it could have overheated, and damaged the topend, or overheated the crank bearings/bottem end. With water in the oil, the tranny could have decided that that was not enough lubrication and damaged bearings/gears. Sounds to me like you should split the cases and inspect everything.

 

[G22inSC]

I pulled the spark plug and found that it was black (carbon fouled) instead of white (which I was expecting thinking it might have overheated). I had only been riding for about 10 minutes when everything occurred, so I am now thinking it did not overheat. I pulled the carb and the exhaust pipe. From what I can see, the piston and cylinder wall looks ok. Is there any other possible reason for the motor shutting off?

I have a little play (wobble) in the primary gear and a slight amount of wobble in the outer clutch basket (not tightened with clutch nut). There is a fair amount of play in the idle and kickstart gear. Is this normal? How much play (if any) should there be in these areas?

On a side note, do Hinson clutch baskets come with the rear gear attached?

Thanks for the help.

 

[YZ165]

First, just because your bike overheats, that doesn't mean the plug will be white. A white plug tip indicates a lean condition, while a carbon fouled black tip indicates a rich condition. Neither of which tell you much about weather the bike overheated or not. If you see small little specs of silver stuck to the plug tip, that may be an indication of piston meltdown. But, if the skirts, and cyl. wall look good, you will have to go deeper to find the problem.

There will be some play in the gears inside the clutch cover, an owners manual should indicate specs for this. As far as I remember, the kickstart gear rides in the right case, and the clutch cover, so it's is going to feel loose if the cover is not in place. Some of the other gears also ride in the clutch cover and will feel sloppy until they are held in place by said cover.

I think you better pull the head and cyl. off and check the top end bearing, and the bottom end bearing and see if that is the source of your rattle. If they are ok, keep looking deeper.

As far as I know, you have to install your ring gear on a new Hinson basket. I've only done three in the past though, all on YZ's, so that may differ with other brands.

YZ165

 

[1sickdude]

Water pump?

Since rebuilding my top end on my rmx250, my bike is running noticably hotter. I was wanting to rule out my water pump. Can anyone tell me how to verify if it's good or bad?

 

[motoracer25]

replace the inner and outer water pump seals