crank seal. should I replace?

[Tin-man]

I am cleaning up a '79 invader I bought a few weeks ago from Lowbanks Ont. The P.O had it for 3 years, and he doesnt know the history. The sled is very complete, and has 150 and 155 PSI compression. I have the motor out, and am checking the crank seals. I can tell they have been done before, but not sure how long ago. I have attached a picture of the seal on the clutch side. Should I proceed and change both of them? I think this one looks really good.

[gixxer6]

The motor is out...Change them...

[mswyka]

When I don't know the history of the sled I change the crank seals.  Actually sometimes when I know the history of the sled I change them.  If they are not changed then there is always this nagging question in the back of the mind whether or not some performance issue might be related to the crank seals.  And as Tom says, the engine is already out - that is the hard part.

[jimvw57]

this shouldn't be a question. Replace them!! If the motor got flooded, in the past years, the seals could have been compromised. Change them and you will know what you got.

[Tin-man]

How do I get that gear off that is in the picture (clutch side)?

[Lloyd (ljm)]

 Dustin

  Bearing pullers will take the gear off. Then heat the gear (set it on a light bulb) and it will slide right back on.
 Like everyone else has said, engine is out. Put new seals in it.

 If you would like any help, you know where I live

 Lloyd

[kawhead]

gonna have to pull the lower crankcase cover.....

[jimvw57]

The crank seals have a ridge that runs around the outside of the seal. If you try to put new seals in without splitting the crankcase, then don't bother to do it. Just throw the motor away. it saves time.

Also, a common failure point is the seal material between the crankcase halves. Make sure you use the correct sealant on them.

[Checkmarks]

If you plan on pushing the sled around the shop with one of those fancy dollys; with a one time start up for the new buyer; don't bother with changing the seals.  If it starts it sells.  Cash in hand before test ride!

If you plan on being able to use the sled with some assurance a piston melt down does not occur (>$150 in repairs{big + your time}), change the seals.  What do new seals cost $15 + some sealant.  The motor is out!  Makes for a very silly question; should I change the seals?

What will you do? 

[Tin-man]

If you plan on pushing the sled around the shop with one of those fancy dollys; with a one time start up for the new buyer; don't bother with changing the seals.  If it starts it sells.  Cash in hand before test ride!

If you plan on being able to use the sled with some assurance a piston melt down does not occur (>$150 in repairs{big + your time}), change the seals.  What do new seals cost $15 + some sealant.  The motor is out!  Makes for a very silly question; should I change the seals?

What will you do?

The question is based on the picture. I dont ask "silly" questions. This is a forum for assistance, not a forum to poke fun. I appreciate your other comments.

Crank seals are being changed.

[jimvw57]

we all have had the "guess I should have changed the seals" blues. Usually out in the middle of a lake with the prospect of a long walk back. Kawasakis are notorious for crank seals failing and the resulting lean mixture melting pistons and cylinders.

Checking the seals with block off plates and injecting air in to see if it holds over time will tell the condition of the seals at that moment, but not when the motor is warm, plus the concern is not if it holds pressure as if it holds a vacuum.  This tests the seals in the wrong direction.

Just about everybody knows about me spending a year working on a sled that wouldn't run right supposedly new seals). When I tore down the motor to use the crankcase on another project, I found brand new seals torn wide open. seems they didn't lube the crankshaft and the first time they pulled it over, it ripped the seals.

Lesson learned. As I often say, Crank seals crank seals, crank seals... It is just cheap insurance.

as for poking fun, we are basically a fun loving bunch. nobody here is paid for the support they offer. Site is supported by the price of the membership, which is nominal, and nobody is excluded from anything by not being a member.  We may give you a hard time for making a mistake but in the next breath we will go out of our way to find that part you are looking for.

[Checkmarks]

Tin,

Jim is way more tactful then me.   There was not intent to poke fun, but more to point out the reality for Kawasaki crank seals.  When a sled will not start and has burned down it has a very low resale value.  Then very low may not describe the value of a non-running sled, when the wife threatens.  There are those who would even pay someone to get it out of their yard fast.

Only trying to help coerce you into the right choice.  If the forum cannot be fun there is no reward for skills helping.  No fun parallels work, what fun is work.

Based on the picture, almost a good point.  Seals are cheap insurance for you ridding the sled for years.   There are plenty of GREAT members here to help you.  I like holding the flashlight while someone else wrenches on their sled (at least the idea).   

[Tin-man]

Many many thanks to LLoyd for helping me with the crank seals!!

They are done. What you see on the outside of the seals do not always tell you the overall condition. After removing the old seals, and inspecting them, they were indeed needing replacements.

[Macs80hp440]

What you see on the outside of the seals do not always tell you the overall condition. After removing the old seals, and inspecting them, they were indeed needing replacements.

Yep- same for me.  I purchased an Invader- then immediately rode it like I stole it.  10 minutes later I melted a set of rings and piston.  For mine, it was on the PTO side- where it ain't as much the culprit.  From the outside the both seals looked fine but I trusted the insight from others and after getting inside I discovered the seals were corroded, pitted, and/or with small tears.  Now I am replacing all seals on my other two motors.