crankcase seal

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ericsbandit

Member

Nov 26, 2002

44

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• Jun 12, 2003

• #1

How much work/ how hard is it to replace a crank case seal?

 

jaguar

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Jul 29, 2000

1,507

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• Jun 12, 2003

• #2

So hard you'll curse yourself for not taking it to a mechanic

 

S

skipro3

Mod Ban

Dec 14, 2002

902

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• Jun 12, 2003

• #3

Amen

 

E

ericsbandit

Member

Nov 26, 2002

44

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• Jun 12, 2003

• Thread starter
• #4

Seriously guys, I don't know much about wrenching on this bike yet. Will I do major damage if I don't get it fixed quick.

 

C

canyncarvr

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Oct 14, 1999

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• Jun 12, 2003

• #5

Everything is easy if you know how to do it.

They are installed from the inside. The cases need to be split, and thus reassembled properly.

If you're handy and don't mind fabricating a tool or two (presuming you don't have a case splitter or suitable substitute) it's doable.

Not something you're going to get a hand-held tutorial on from this site most likely.

1. Remove all the extra stuff (FW, clutch and such)
2. Split the cases
3. Replace seals
(note)* Doing a big-end rod bearing may be something to consider at this time. That involves crank dis/reassembly. THAT involves truing the assy.
4. Reassemble

Piece-o-cake.

For the masses, it's a lot of work and mucho hard. Probably not possible.

imo and all.

I recall seeing the 'split cases' charge at FRP being $150. I'll bet'cha they know what they're doing and have the tools to do it....and it's STILL $150.

Not trying to make a big deal out of nothing...but replacing inside crank seals is a fairly big deal.

Have fun, though!!

 

C

canyncarvr

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Oct 14, 1999

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• Jun 12, 2003

• #6

Gee..if I didn't take so long to write a reply...I wouldn't see it covered already. Hey! Work interrupted me!!

re: damage if I don't

Depends. If you're sucking tranny oil, the possible outcome is (obviously) loss of tranny fluid and transmission failure.

If you're blowing AF mix out of the crankcase, you're diluting the tranny fluid, the possible outcome is (obviously) more tranny fluid ;) and transmission failure.

If you're sucking air into the crankcase, the possible outcome is (obviously) a lean seizure which may cost you a cylinder and a piston.

Get the idea? It could be a very bad thing.

 

Last edited: Jun 12, 2003

E

ericsbandit

Member

Nov 26, 2002

44

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• Jun 12, 2003

• Thread starter
• #7

I don't think that the oil level is going anywhere. It's been the same for the last couple of rides. I think I am starting to worry too much. Last night I went over to a friends house to do some wrenching and he thought that the bike may be running rich due to needing a new top end, so I asked here and then someone mentioned that it may be the crank case seal, more worring. I'm going to Colorado next week and I don't want to blow the tranny. If the crank seal was bad, how discolored would the oil be? i changed it last month and it wasn't white or to discolored. Am I worring to much?

 

J

jdbrusch

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Nov 11, 2001

185

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• Jun 12, 2003

• #8

Are you having trouble with plugs fouling or are you losing tranny oil or is it just for peace of mind,you can have a leak down test done on the motor to see if the seals are still good,it pressurizes the crankcase and top end to check for leaks.This does not indicate a worn top end though,it just tells you how air tight the motor is.If the bottom end is ok,no leaks,you may just need a top end (piston rings etc) and a good clean up.

 

C

canyncarvr

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Oct 14, 1999

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• Jun 13, 2003

• #9

Based on the original post, there wasn't a question about bike condition/operation, just how-to replace the seals.

Starting at the beginning is probably more beneficial to resolution of the problem.

Basic biking 100: If you haven't rejetted your bike, the chances of it running poorly due to being too rich are excellent. IF the original complaint is 'too rich' I sure wouldn't be jumping on the crank seals.

BTW, too rich (or not) is determined long before the 'top-end' has anything to do with the A/F mix.

 

jaguar

~SPONSOR~

Jul 29, 2000

1,507

82

South America

• Jun 13, 2003

• #10

I'd suggest taking off the ignition cover and seeing if theres any dark oil there (laying on the bottom). If so then that indicates a blown left side crank seal (which probably means the right side seal is blown also). Usually that predisposes the bike to a lean seizure but if you're not riding hard at top rpm's then you probably won't seize it. There's a lot of KDXes runining around in need of crank seal replacement. But if you don't have the tools and aren't very experienced at working on bikes then I'd let a good shop do the work.

 

7

70 marlin

Mi. Trail Riders

LIFETIME SPONSOR

Aug 15, 2000

2,960

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• Jun 14, 2003

• #11

Let FRP or Mr Gorr do your work! The job isn't for the MEEK! sounds like jetting to me. "watch your tranny fluild level"

 

K

KDXJP

Member

May 21, 2002

16

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• Jun 14, 2003

• #12

My1990 KDX had a leak inside the ignition cover(A teaspoon or so of old gas and oil). I had the seals replaced two summers ago! My bike has not been ridden for about a year. Im hoping the seals will re-seal after a couple of rides
if not then Ill do the split thing.

 

G

G. Gearloose

Pigment of ur imagination

Jul 24, 2000

709

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• Jun 14, 2003

• #13

JP
If I took my engine to get split every time I saw condensed gas in the mag cover, I'd give up biking..

If your bearings are good (hopfully you put fresh ones in last split), first visually inspect the seal under the flywheel.

It its dry, cracked, torn, missing, blown inside out or you find the seal's spring in the bottom of the mag cover, etc, then by all means fix it.

A pressure check is best assurance, of course.

If it appears the same nice condition since servicing it, I would seriously consider it adequate with a posiftive pressure check, and worthy of checking on periodically, but not worth splitting the case over a teaspoon of condensed gas vapor as the single deciding criteria
I'm confident my mag cover is airtight, else it would have reduced to a thicker oil over 6 months of inactivity. Also else I would have seized the engine when I rode it for years with he seal blown completely inside out.

I was mortified to see gassy liquid after doing the full split last year, after just a few rides, but the seal is in tact, looks as good as the day I got the case back, and gliding on the crank nicely.

I'm just going to ride it.. I'm confident mine is sealed now, despite the bitty gas. something to consider..

 

jaguar

~SPONSOR~

Jul 29, 2000

1,507

82

South America

• Jun 14, 2003

• #14

G, I think what you saw was just moisture condensation, not gas. Everyone gets condensation under the ignition cover if its sealed good.
What u want to not see is dark oil. That is definitely due to seal failure.
I think replacing the crank seals every 2 years is normal.

 

K

KDXJP

Member

May 21, 2002

16

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• Jun 16, 2003

• #15

I rode this weekend and a small amount of water dripped out. It smelled like watery gas. Not a big deal. Yes, I did change the main bearings with the seals.