KDXRIDER.NET

I’m getting more than just a bit frustrated with the leak from my countershaft seal on my 87 KDX.

The Kawasaki parts diagram show that unlike my 92 model it does not require any o-rings behind the seal. I have recently replaced it (again) and as usual it has failed. The sealing sleeve (spacer) that slides over the shaft and into the seal couldn’t be in better shape and the bore that the seal resides in couldn’t be improved on.

I’m certainly open to any suggestions. I just ordered a couple of new seals and I hoping to have a different result.

A lot of people end up cleaning that area meticulously with brake parts cleaner etc, & using RTV silicone to completely seal the collar/sleeve onto the countershaft after even putting in the o-ring. KTM's have a reputation as calling this leak the "KTM automatic chain oiler."

Is the back of the sleeve/collar completely flat? I would find it odd that there's no inner seal, as oil can absolutely leak past that with no other ceiling method to keep oil out of that area.
If one side of the sleeve/collar has a taper like the later KDX, or a 90° step on it like the KTMs, then it absolutely should have an o-ring there. I can't imagine any possible way that could seal oil in at least without it intending to be installed with case sealer / RTV silicone. Have you consulted the factory service manual?

Even my 1977 Suzuki PE 250 has an o-ring there, and the collar has provisions for the o-ring as well.

Here is a pic of the business end of the sleeve that goes into the seal. It does have an internal chamfer that could possibly be to accommodate an O-ring. I have looked in my hoard of O-rings and I don’t have anything that size that is thin enough to try.

The problem is that the parts diagram don’t show or list an O-ring so how do I determine the size needed?
I measured the outer edge of the splines on my 92 model and on my 87. It appears that they both have a 25mm shaft. I suppose I could order an O-ring for the 92
and see if it works it would have to be pretty thin to not interfere with the sealing lip on the seal against the sleeve.

I posted a minute ago but don't see it showing up. Go to Partzilla.com and pull up the transmission diagram for your bike. Its supposed to have an oring.
Part number 92055-035 for the 87 KDX200

Make sure to stick a small metal 90 degree or hook shaped pick in there and check that an old oring isn't jammed back there before installing the new oring.

Edit: It is the same part number for the 92 also. The 92 takes 2 orings and the 87 takes 1.

Hmmm. I’ll give that a try. I assumed the Kawasaki parts diagram would be accurate but maybe not. Thanks for the tip.

I took a close look inside when I installed the new seal and didn’t see any sign of an O-ring. I completely rebuilt this bike several years ago and I either used the Kawasaki parts diagram as my guide or if I put an O-ring in it has completely deteriorated.
When I ordered the new seal and that I installed it a few days ago I was actually surprised to see that according to Kawasaki it didn’t require an O-ring.

Partzilla & generally all OEM parts suppliers use the official Kawasaki diagrams, but perhaps yours is just not as detailed? Where are you looking it up at?

That collar / sleeve with the chamfer/taper ABSOLUTELY is designed to have an o-ring there, and will ALWAYS leak without it.

Crap! I was looking at this diagram.

https://www.partzilla.com/catalog/kawas ... /crankcase

I actually hadn’t ridden this bike for quite a while. I moved from Oklahoma to New Mexico a couple of years ago and had to go through a lengthy process to get my KDXs registered in New Mexico. Oklahoma didn’t require registration for a dirt bike. I finally got the registration for both bikes and was able to get the off road permit that is required to ride an OHV vehicle on public land.

I finally took it to a local riding area. It hadn’t leaked a drop sitting on its stand but about halfway through the ride I noticed the leak. I was able to finish the ride keeping an eye on the sight glass. It did not disappoint. I was riding some pretty gnarly singletrack with a few riders on much more modern bikes and they were definitely impressed.
It’s an extremely capable bike and very easy and comfortable to ride. Next I’ll be taking my 92 model out on the trail for the first time. I finally fixed a pesky fuel tank leak and rebuilt the rear caliper and slave. Now I am just waiting to receive the Forest Service sticker and I’ll be good to go.

Thanks for the tips and setting me straight on the o- ring.
Here’s a couple of pics of my bikes waiting to be put to use.

The '86-'88 KDX200 truly is the best air cooled trail bike of all time, aside from those requiring the raw power of a big bore, in which case Id recommend a Yamaha IT465 or maybe last year or rwo of IT250 if the 200 was just shy of needed power.
The '88 KDX200 certainly is the pinnacle for me. If I found a good one for sale after I get my Suzuki PE250 & PE175 mechanically rebuilt, I certainly would be looking to trade up... Although the '77 PE250 is a great bike with low seat height that my 74 year old Dad can cruise on...

The '86-'88 KDX are incredible machines. A Lectron carb on an 86-87 would be the only big thing I'd change besides fork internals or a DRZ250 fork swap...

Chuck78 wrote: ↑03:10 pm Sep 11 2023 The '86-'88 KDX200 truly is the best air cooled trail bike of all time, aside from those requiring the raw power of a big bore, in which case Id recommend a Yamaha IT465 or maybe last year or rwo of IT250 if the 200 was just shy of needed power.
The '88 KDX200 certainly is the pinnacle for me. If I found a good one for sale after I get my Suzuki PE250 & PE175 mechanically rebuilt, I certainly would be looking to trade up... Although the '77 PE250 is a great bike with low seat height that my 74 year old Dad can cruise on...

The '86-'88 KDX are incredible machines. A Lectron carb on an 86-87 would be the only big thing I'd change besides fork internals or a DRZ250 fork swap...

Yep. They’re fantastic bikes. Mine is completely stock except for a shock revalue and rebuild. I ride in rocky terrain at the local trail system and the forks are nicely compliant, forgiving, and don’t tire me out as quickly as most bikes. I’m thinkin’ between my 87 and 92 model I’ve got the right bikes for the conditions here. But I might need a H model to round things out. lol

I’m almost 59 and I think the comfort and forgiveness is gonna keep me going for quite a few more years.

Yessir...
I've got a '97 KDX220R & a '99 version of the same (temporarily retired until rebuild), & I'm in love with the 220 engine... Have the head modded for proper tighter squish and dome cut to get the cc's correct for punp gas after squishing(milling), add a Gnarly Desert Pipe or preferably Pro Circuit Platinum 2, rejet the carb with a JD Jetting kit, or add a Lectron Billetron Pro Series carb, & you'll have the best of all KDX's... Although an '86-'88 with a disc brake rear conversion and fork upgrade, PowerDynamo/Vape ignition upgrade, + Lectron 34mm carb... That'd tempt me pretty heavily to say its a better cooler bike than a 220...
But an 89-94 with fork upgrade and a 220 engine... THAT would be really REALLY AWESOME...

Are you aware of the flywheel magnet epoxy problems on the '86-'88? Might I suggest if it's still original, absolutely look into cleaning it up substantially and filling it with epoxy in between the magnets so it doesn't self destruct?
Or upgrade to a Vape/PowerDynamo system or learn how to re-clock an 89-94/95-96 stator plate to run it and the corresponding rotor/flywheel on the 86-88. They're about 90° out of time, and new slotted mounting hiles need milled into the 89-06 stator plates to run them.