Leaky Crank seals, help?

[John]

Wouldn't you know it...as soon as the 'take it easy' period was up, the bike went down. No, I didn't get right hand stoopid or anything like that. My crankshaft seals were leaking, so I ordered a set from Bike Bandit. They came in last week, and I waited until Thursday to change them. I thought I'd tempt fate and not split the cases. I pried the old seal from the left side with ease. I trimmed the rubber from the ridge on the new seal, and filed the metal down to match the outside diameter of the rest of the seal. I fiddled with it, and got it to start into the bore. I placed a block of wood over the seal, and gave it a few whacks with a hammer. I thought it went right in...but I was wrong. The edge of the seal caught on the case, and rolled on me, trashing the seal. I ordered a new seal right then. I still think I can do this without trashing another seal. I have read here where a couple of guys have had success cheating this way. Anybody have any input? Any luck doing it without splitting the case? The right side seal doesn't have the ridge on it like the left one does. I hate the thought of having to pull the engine out just to replace one lousy seal. Be just my luck I'd scratch the hell out of the paint trying to pry the cases apart.

[skids]

Re: Out of Service

I suggest that you start a new thread concerning your question. You might get more readers/responders that way.

Originally posted by John
The edge of the seal caught on the case, and rolled on me, trashing the seal. I ordered a new seal right then. I still think I can do this without trashing another seal. I have read here where a couple of guys have had success cheating this way. Anybody have any input? Any luck doing it without splitting the case? The right side seal doesn't have the ridge on it like the left one does. I hate the thought of having to pull the engine out just to replace one lousy seal. Be just my luck I'd scratch the hell out of the paint trying to pry the cases apart.

[TopCatGr58]

Hey there Skids,

I split his thread for him. John, are these new seals that you put on the bike when you did the rebuild?? I would be very surprised to see them leaking. I thought you split the cases when you did your rebuild, unless I'm remembering someone else!?
Sorry, can't help you with the seals problem, still have my OEM's in!
T.C.

[John]

TC

I didn't replace the seals when I did the big bore. They weren't leaking in the old motor, so I assumed... New seals didn't come in the gasket set like I thought they would. They were replaced 10 years ago, but they only had 4 years of use on them. They weren't hard or brittle when I installed them, and I used lots of assembly lube. That'll learn me..

[ratbyk]

Seal Leak

John, is it possible that excessive crankcase pressure started your seals leaking in the first place. If your rings/pistons/cylinders from the big bore job have not seated in you could have too much crankcase pressure for the seals to contain. Make sure that the crankcase vent hose off the back of the crankcase by the middle gear is open without any kinks or other restrictions. If not your new seals may start to leak as well.
Ken/Sooke

[strom]

I have the same problem....
vent hose is OK
I installed new seals, and I split the crankcase to do it. I was also careful, that the seal was installed properly. No XSive force used, no mallots or any of that.
The seal starts leaking even when I turn the engine over using the starter motor (spark plugs out).
Weird. The old seal leaked, so I replaced it with a new original one from my yammie dealer and same thing.
I'm open to suggestions.

LP

[ratbyk]

Leaking Seals

Only suggestion I have is to pull the vent hose off or at least the end that plugs into the air box. Run the engine warm and observe how much blow by gases are coming out and if any excessive pressure is being built up. There should be some but if excessive it would be obvious.
If excessive it indicates that the pistons/rings.cylinders are not sealing compression/combustion pressures. Could be unseated rings, sloppy pistons, scours on the cylinder walls, broken ring lands on the pistons or combination of all. Only solution is to pull apart and fit a good set of pistons/rings into straight round cylinders. Excessive blow by will not cure itself. Replacement parts are needed.
Ken/Sooke
78E Ratbyk
82 FT500 "lilRat"

[strom]

I just installed new piston rings (std), and had cyls. honed.
But the thing should work like this: more pressure, the more it holds....
We'll see.... I need a valve shim (0.235). I'll grind one of extras I got.

LP

[ratbyk]

Blow By

If you just put rings in possibly they are not seated in yet.
Hopefully when the cylinders were honed they just broke the glaze and did not remove anymore metal than necessary. If you used the same pistons in holes that have had an excessive honing your piston skirt to cylinder wall clearances will be too great. When you start to have .003' to .005" clearances from skirt to cylinder wall you are going to get blow by. The pistons are not big enough to fill the holes anymore. .005" would be all right for a racing engine but on a a street/everyday type engine .005 is excessive.
Ken/Sooke
78E Ratbyk
82 FT500 "lilRat"

[strom]

Didn't start the bike with new stuff in yet....
I was at work from 8 am to 4 pm, got home, made coffee, and been putting the bike back together till 10.30 pm.
Got the head back together today, checked valve clearancies, all OK but two.... got 3 shims from a friend that used to have a XS11. One was a perfect fit, the other one gotta be grinded down a bit.
Tommorrow.
carbs, exhaust, etc too....
I hope....

LP

[Jdwags]

left seal

I did my left seal without splitting the case.. ground down the lip on the seal and tapped it in.. mine rolled on me so ive ordered another one, and it does leak..
one of the old dinusar's (sp) at the shop, thought it might work.. i do know there is some oil flow on the back side of that seal so its tempted to leak a bit if it's tweaked ..


i know i knicked the inside when it rolled so im hoping that was the problem but it leaks less now than before..

(glad that seal was only $3.99)..

they should sell them in pairs.. 2 lefts 2 rights.. lol

[digitalsam]

I have a leaky seal on the right side. It only seems to leak at start up. Maybe until pressure builds? (an uninformed guess). Does it indicate a train wreck waiting to happen, or can I get away with letting it leak. I really don't want to crack the cases if I don't have to. Can I install new seals without cracking the cases? New gaskets are expensive.

[XJOK2PLAY]

Sam,
There was a recent thread on here somewhere the other day about this topic... even has pictures of the 2 seals.

I just replaced the one on the left side of my XJ a few weeks ago. I did the same as the the previous guy stated he had done...

Ground down the outer rib smooth, but I placed Yamabond all around the outside of it before tapping it into place, and placed a light coat of oil on the inside lip... and let it set up for 3 days before I rode it again.

The seal w/ the lip is the stock one from Yamaha. There is an aftermarket that doesn't have the lip.

So far, mine's leak free.

Haven't had to address the right side... yet. So I don't know what to tell you there. Thinking it's just the mess of an oil leak, though.

[motoman]

Grind it?...........turn it around the other way.....put it in........go ride.

[XJOK2PLAY]

Yep, that's what I'm now hearing... AFTER I've done it the hard way, of course!

I did consider that, but wasn't sure it would go up in there far enough if turned around... by grinding it down, it goes all the way in... another 1/8" or so... but guess it doesn't matter & I was just paranoid...

All I wanted was to stop the friggin' leak! (For good!) (Which I did.)

I was getting sick of oil sprayin' all over my nice new TCX boots...