KTM300 Spewed oil From vent?

[XT]

I have a 98 KTM300 MXC. When I got back from a ride today(not overly long and not too hot) I noticed oil dripping from my swingarm/shock area. Thought I had blown the shock on a nasty G-out. Upon further review, it appears that the tranny just spewed a bunch of fluid. It was all over the airbox shock swingarm and airboot. This has not happened to me before. Any ideas on the cause? Bike is rinning fine, I'm pretty sure the crank seals are OK. Stumped!

 

[ktmike55]

did you have any falls whre the bars were lower than wheels, like off the side of a trail where it was hard to pick the bike back up oil gets trapped in the vent hose then makes a mess when you get back riding. also the bike only needs 800cc of oil. if over filled also messy.

 

[Buckholz]

Make sure your vent tube didn't contact the expansion chamber and melt thru the vent tube, has happend to me on my 98 and 00 KTM380. Replace vinyl vent tube with rubber fuel line, jamb it up into the hole in the frame at the top, so it is pretty much straight. Less chance of bending and hitting the exp chamber.

 

[meddle1999]

water pump seal, water pump seal , water pump seal...... When you order your new seal get 2.
you'll need 'em.

check the impeller shaft and bearing for wear and/or corrosion. replace if needed. A good prevention for this VERY common problem is to run an alternative coolant such as "engine ice" or "watter wetter" . I use Watter wetter with low tox propelene glycol (instead of ethelyne glycol) mixed 70/30 with distilled water. This has greatly extended the life of the water pump seal.

As i said i wouldalmost gaurantee that this is your problem.

 

[ktmike55]

Also very messy if water pump seal is out, when you change the oil youll need to do it twice the first time all youll get out is white goop.
good call meddle. I have also experenced this. if its white goop this is the problem.

 

[XT]

I think it was over filled. It was clean oil that came out. I used the oil level bolt to determine the level. I guess that I'll stop using that and just use 800cc.

 

[Guaryzzzpode]

It's just over filling. In fact, the 800cc might be a bit too much, because when you change the oil, about 50cc are still left in the bike. I go with 750-775cc.

 

[DanS]

I overfilled mine a couple weeks ago before a race and when I was warming it up on a short ride I had the same thing happen. Thought I had blown the shock seal. It eneded up just being clean engine oil. Kind of makes you sweat a little until you figure it out.

 

[Strick]

Originally posted by Guaryzzzpode
It's just over filling. In fact, the 800cc might be a bit too much, because when you change the oil, about 50cc are still left in the bike. I go with 750-775cc.

This would be my take also. Unless like one of the other posts mentioned the oil is discolored (milky), or a crank seal is bad. I too always put in 750cc in my 300. My theory is you can never get all of the oil out of the crankcase to get a full 800cc back in.

 

[ktmike55]

Great thats alot better than water pump seal! Im online with another Guy from Abq. were talking about colorado trips for this summer you might know him John O ?