Leaking Crank Seal?

[Racinante]

I haven't performed a leak down test yet on my '91 KX 250, but I'm almost positive I have a right side crank seal leaking. When I look inside the crankcase, either through the exhaust or intake, I see massive amounts of oilly buildup. My bike runs great on top end, but craps out on bottom. It smokes a lot on bottom too. I've checked out every other part of the bike from carbs, jets, air filter, reeds, to top end compression. I got 150 psi with that. I'm getting ready to check primary compression, but I'm sure one or possibly both crank seals are leaking.

Does anyone know if it's possible to replace the crank seals on my '91 KX 250 without splitting the cases? If it is possible, got any tips?

 

[itsamelee]

think i can help!!

i think you can change the right seal without splitting the cases...
the right seal would cause your bike to smoke
as far as the left one ,, i dont beleive it is ,,,,,,the reason why is
it would rev really high without giving it any throttle
oh well, while your at it you might as well check the crank berrings
just grab the crank and try to wiggle it up and down
if theres no play,, put a fresh seal in it and have fun
gotta go

 

[spanky250]

Sorry, but you have have the same engine as me, and you have to split the cases to replace the seals :(. You might as well rebuild the bottom-end while your in there.

 

[Racinante]

I was afraid of that:mad:
You helped out a lot before when I was trying to correct the problem by leaning out the pilot jet. I went all the way down to a 42, and wasn't making any headway. I was hoping I could find a simple solution, but if I have to split the cases, I will go ahead and rebuild everything. I do want to perform a leak down test first. But, there's not really anything else it can be. I did have a water pump gasket leaking and filling the tranny with oilly froth! (It's fixed now) Do you think anti-freeze could cause the seals demise? And if so, it could have possible damage my berrings, couldn't it?

You have your engine ported don't you? I think I might call Eric Gorr to see how much it would cost to have him rebuild the bottom and top, and possibly port it to run a lil' smoother for trail riding.

I'm temped to buy one of his videos and do it myself (to save some ca$h) but it might be better to have someone more experienced do it, if they can make some changes to help it's trail manners.

Did you do your engine yourself, or did you have someone else do it? If I can replace a turbo on a mazda 626, without a manual, do you think I could tackle this one myself?

Thanks for the info!

 

[spanky250]

Originally posted by Racinante
I did have a water pump gasket leaking and filling the tranny with oilly froth! (It's fixed now) Do you think anti-freeze could cause the seals demise? And if so, it could have possible damage my berrings, couldn't it?

If you are running antifeeze that contains silicates, that can be a contibuting factor in a leay water pump seal. It can also be nothing more than the seal was worn out from use. As to the tranny bearings, unless you rode it a lot with water in the tranny, I wouldn't worry.

Originally posted by Racinante
You have your engine ported don't you? I think I might call Eric Gorr to see how much it would cost to have him rebuild the bottom and top, and possibly port it to run a lil' smoother for trail riding.

Yes, my engine is ported. It is a double-edged sword, because I made a poor choice when I sent it to FMF for the work. I got back an engine that has far more power than it did stock, but it hits harder and is more difficult to control in poor-traction situations. They gave me an off-the-shelf port job that was obviously intended for a very fast pro, which I most definitely am not.:D If I had it to do over again, with eveything I have learned here, Eric would have done my engine.

Originally posted by Racinante
Did you do your engine yourself, or did you have someone else do it? If I can replace a turbo on a mazda 626, without a manual, do you think I could tackle this one myself?

I did the disassembly/reassembly work myself, with the help of a few borowed tools (like a case splitter). If you do decide to tackle it yourself, a manual is a must. To be truthful, I think the next time I need to split the cases, I'm just going to let a shop do it. I just don't have the free time with the job, kids, etc...

 

[spanky250]

oops!:confused:sorry about the double post!

 

[Racinante]

Hey thanks for the info!!! It's amazing, I've gone to three different shops in the area and received three different results. One told me it would be about $50 bucks to replace the seal and they were pretty sure they wouldn't have to split the cases. The other two weren't to sure, and they could only tell me if I brought my bike in. One of them was an authorized Kawasaki dealership! I don't think I'd trust any of these guys if all I needed was a spark plug replaced.

I just hope Eric is reasonable. I've only heard good things about him though. I just have no idea how much it would cost to send him my whole engine. That would be the best scenario for me if I can manage to scrape up the funds.

 

[Ricky]

I just hope Eric is reasonable. I've only heard good things about him though. I just have no idea how much it would cost to send him my whole engine. That would be the best scenario for me if I can manage to scrape up the funds.

He is reasonable and very helpful. He has one of my top ends right now. Call them and they will send you a free shipping crate to box your motor up and send to them. Eric doesn't do the bottom ends. Jim Neupert of 2-Fast does, he rebuilt a bottom on my sons bike, I am very happy with his work as well he is also very reasonable. :)

 

[Patman]

Something to consider. I had the ignition side crank seal go at Dirt Week. While talking with Eric I'm pretty sure he said that the first thing he used to do with Kawasaki engines when he work for (??? TUF maybe) was to split the cases and bore the crank seal that was a back side access only. Might be worth the few extra bucks to get done to make future replacement easier.

 

[Weezie]

I feel your pain. I've got a '92 KX 250 in the basement right now split and ready to be rebuilt. My piston shattered and I decided to split the cases to look for damage. Cases were cracked on both halves(crank housing). My buddy welded them up for me, you'd never know they were broke. Hope they hold!! But anyway you have to split em to replace the seals. I found a kit by Moose that has all the oil seals and gaskets for around 70 bucks. I'm assuming it's got crank seals in it to. I gotta find out. I also found a couple bad bearings. If you don't have a manual, I highly recommend one. Good luck, don't be shy, get your hands dirty, do it yourself. I've learned so much about bikes by doing it myself. Later, Mike:confused:

 

[spanky250]

Originally posted by Racinante
It's amazing, I've gone to three different shops in the area and received three different results. One told me it would be about $50 bucks to replace the seal and they were pretty sure they wouldn't have to split the cases. The other two weren't to sure, and they could only tell me if I brought my bike in. One of them was an authorized Kawasaki dealership!

That's pretty scary when a Kawasaki dealer "isn't too sure" how to work on a Kawasaki. It's not like the KX 250 engine has been changed a lot over the years.