Leaking oil around sproket shaft

[m37]

My bike started leaking oil around the shaft where the front sproket is located. It is leaving a large puddle overnight. Is this seal a big problem to replace? When adding oil to transmission do you fill till you see the level in the sight glass or do you fill to the top of the sight glass?
Thanks!!!

 

[David Trustrum]

Best time to replace that seal is when you have the gearbox apart. Yeah ok, back to youir problem. Drain the oil. Take the sprocket off.

Pull the seal out. It may lever out with gentle use of screwdrivers (but use your head & at all costs don’t lever against the shaft as that is what it seals on). If this is proving hard you can drill a couple of holes & wind in some self-tapping screws to purchase on. Again look where you are drilling.

Slide the new (& greased) seal over the shaft. It is best to run a bit of tape over the shaft so the seal isn’t torn on it. Tap the outside edges of the seal evenly into the original resting place.

 

[kdxtaz]

That seal can be changed w/out splitting the cases, but usually requires patience and finesse. Someone posted a while back (I forget who) about finding dirt trapped in the seal & just cleaned it with good results. I fill the oil to the top of the glass, obviously with the bike standing straight up.

 

[jaguar]

I replaced the seal and the bike still leaked afterwards. The problem was that the collar that it sealed onto was grooved. After replacing it the problem was gone.

 

[JasonWho]

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[bully1027]

Originally posted by m37
When adding oil to transmission do you fill till you see the level in the sight glass or do you fill to the top of the sight glass?
Thanks!!!

my fill window is the same color all the time, i cant see where the line is, i just measure .8 liter and drain the case and refill with the full amount. i put a bucket under it at night and measure the leaked amount and then refill that amoung plus a little more because i proably lost some oil on the trail:]

 

[Jasle]

Originally posted by JasonWho
Hello, and thank you for all the replies. Can the shift shaft seal and kickstarter seal typically be replaced in the same manner? I am asking concerning an '87 KDX 200.

Thank you,
JasonWho
'94 KDX 200 (300 miles)
'87 KDX 200 (300 smiles)

Yes! I have even done crank seals this way but you gotta be CAREFUL!!!!!! or you scrap the crank.
Jason R

 

[jaguar]

if you can't see through the sight glass then you should take the cover off and clean the glass. It's important to know what the oil level is.

 

[Canadian Dave]

Yes as previously posted the seal is often packed full of grim and you can some times get a little more life out of it if you gently pull back the outer lip and rinse it out with something like WD-40. You do however run a slight chance of pushing some of that grim into the transmission so do so with caution.

If/when you pull the seal out you need to remember to do a couple things. There are two seals, the first you can see, it’s a lip seal, the second is an o-ring. When you remove the seal you’ll see that where is a wear bushing installed between the output shaft and the lip seal. The o-ring is located between the shaft and the bushing and prevents it from leaking. Have a look at the bushing and you’ll very likely see that it has two grooves warn into it from the lips on the seal. If the grooves are very slight you could likely install a new lip seal and no oil would leak past. Your best bet however is to remove the bushing and o-ring. Inspect the o-ring (they are normally fine) and if it’s in good condition reinstall it using plenty of grease. If its not obvious be sure to check its location before you remove it so you can ensure its reinstalled in the same location on the shaft. Next you want to reverse the bushing, so the seal’s lips are running on a fresh surface, grease it well inside and out and reinstall it over the shaft/o-ring. I find that it helps if you slide it over the shaft until you just make contact with the o-ring then slightly rotate it so it slips over the o-ring. Just ramming it over the o-ring will likely roll it out of position. Once you’ve got the shaft and o-ring installed grease the seal and install. The next time you replace the seal you’ll likely need to replace the bushing, it will now have 4 wear grooves in it.

Hope that helps,

David

 

[m_champoux]

I'm also having the same problem !!

The real problem is that my dealer will receive the parts at the end of the week.

To my fellow KDX, Do you think I can ride with a little bit of oil dripping ?
(It leak oil when the bike is on the stand, not while standing)
(I opened the rings and cleaned them but it still leaking a little bit)

I think if I check the level often, I should be OK !!

Thanks for your advice !!