Crank Bearing Seal Replacement?

[WildBill]

I have a '90 kdx200 and I'm looking to replace the seal on the clutch side of the motor as I believe it is leaking, pressurizing the crankcase and forcing oil up into the airbox through the vent tube. :ugg: My question is, can this be done without splitting the case? Any help would be appreciated.

 

[lankytim]

I'm about to replace crank bearings and seals on my 1999 KDX200 and as far as I understand, it requires splitting the case halves because the seals are inserted from the inside of the case. Sorry, dunno if the 1990 engine is different. Good luck.

 

[WildBill]

Thanks for the info., that's what I was afraid of. Good luck to you as well.

 

[Dogz]

Just checked the Kawi service manual and you do have to split the case to do the seals. Oh well its a chance to do the bottom end.

 

[Boot]

Yes, you sure do need to split the cases unfortunately. I wish they made these engines with a bolt-in seal carrier or something. I just bought a pair of seals yesterday, and have my cases apart ready to do a big-end rebuild on it.

If you want to do it yourself, search on 'splitting cases' in this forum, and you'll find some helpful hints from those who've gone before. It's tricky, but do-able.

The seals themselves can be bought from a bearing wholesaler for a lot cheaper than the Kawasaki parts. Just ask for seals that are 40mm OD, 25mm ID, 7mm thick. A pair cost me $8.00 Australian.

Good luck with it.

Boot
Melbourne, Oz
85 Virago 1000
91 KDX200 (240SR)
http://www.copperleife.com/craig/bikes/kdx

 

[WildBill]

Thanks guys. I don't know if I will tackle it now or wait until winter. My only symptom is that I think is causing the pressurization of the crankcase forcing trans oil up through the breather tube into the airbox. We're not talking much, and the oil level does not drop below the minimum level. It just nasty up the airbox and I know it is not proper, so I want to correct it.

Is there any other damage that this may be causing?

Thanks again for the replies.

 

[Boot]

You can suck transmission oil in through the seals and coke up the engine. Apparently you can suck air in through the seals too and end up with a lean mixture condition, which could burn the piston, or whatever. Neither of these things are necessarily happening in your case. Just be on the lookout for telltale signs (excessive smoking / hunting, overheating, etc).

If you pull off the alternator cover, you might find dark sludge sitting below the rotor. This would be another indicator of leaky main seals, though again, it's not necessarily the end of the world.

Cheers,

Boot
Melbourne, Oz
85 Virago 1000
91 KDX200 (240SR)
http://www.copperleife.com/craig/bikes/kdx

 

[Canadian Dave]

Just a word of advice, if you are going to split the cases to replace the seals you should seriously consider rebuilding the crank and replacing the crank bearings as well especially if you have to pay someone to split/reassemble the cases as much of the expense is in the labor.

If you are looking for a less expensive way to purchase a crank rebuild kit search ebay for both 1989-04 kdx200/220 and 1988-91 KX125 as the con rods are the same. You can also take your crank and transmission bearings to a local bear supplier and have them match them up. You can normally save about 50% over dealer’s prices. They can often match up most of the seals as well.

David

 

[wibby]

Hey WildBill, How's your topend?
I've got a '92 that was doing the same thing. I had to clean my air filter after every ride!

But it stopped after I put a new topend in. :clue:

 

[WildBill]

Thanks again guys. Wibby, I rebuilt the top end last spring and it did not stop the problem. The bike runs strong and there is nothing leaking to the magneto side. I have the same problem with my air filter.

Anyone know about how much a shop would charge to split the cases and install new bearings and my new seals? I hate to keep putting money into a 14yo bike, but it is in good shape and all tuned to fit me suspension-wise.

Thanks,

 

[G. Gearloose]

I can look up the invoice when I had similar work done on my '91 when I get home, if it helps.

 

[WildBill]

Gearloose,

If it's not too much trouble, it would be appreciated.

Thanks,

 

[sunnyboy]

i would think that if your seal was bad you would also be sucking oil into the engine aswell strange--it has been a longtime since i have done a seal with out spliting the cases but it can be done by using a couple of sheet meatal screws and screwing them in to the seal and using them to pull the seal out.however if one seal is bad the others are not far behind.also check your crank end and check it for play lots of times it is not a bad seal but the crank is moving around and the seal cant do its job

 

[Boot]

Actually, you can't really do the screw-extraction trick with the main seals. You might be able to get them out with a lot of mangling, but you'd never get new ones back in. There are metal lips cast into the cases that make the seals a one-way replacement (from the inside, unfortunately).

Boot
Melbourne, Oz
85 Virago 1000
91 KDX200 (240SR)
http://www.copperleife.com/craig/bikes/kdx