crankshaft seals?

[sljsmc]

Ok, so I read on here to change the crank seals. What do most of you use for a guideline?
Do you change them every year every other year etc. what kind of interval do you go by?
Thanks Steven

[Interceptor398]

As needed.  I prefer a leak down test, it is fairly simple to do once you have the stuff.  Then you only need to pull the motor when something is really wrong.

[gixxer6]

I don't think crank seals ever real "wear out".  But the rubber does get old and deteriorate.  When that happens they will fail.  As long as you run the sled often and keep them lubricated, I wouldn't worry about changing them for 10 years or so. 

[mswyka]

Our experience has been that the sled will start to backfire occasionally just prior to total seal failure.  And 7 or 8 times out of 10 it is the mag seal that goes first.

[JDmatt]

This is a good question.  I rebuilt the Kawasaki fanner in one of my JDs about 5 years ago.  I'm thinking about doing a leak-down test on it just to make sure they are still good.  I ride it every year, so in theory if everything is kept lubricated they should last a while, as opposed to a barn find that may have been sitting for a decade or two. 

[jimvw57]

Flooding a motor and then letting it sit is particularly tough on seals. If your carb needle and seats leak, it is a good idea to do the crank seals. The fuel washes the oil off the crankshaft, and dries out the seals. Soon they crack or worse yet stick to the crankshaft and tear.  Same can happen with a fuel pump leaking fuel into the crankcase...

[5kaws]

I did my drifter 440 motor last weekend , took 4 hrs between pulling motor out of sled and replacing  all gaskets and seals.  My pto side was blowin out lol. And the mag side was leaking a little.   Better to replace them now , because what could happen is the spring on the seal can get sucked up into the motor and that 40$ fix will jump to $?$?  Just my input because it has happened to me one time.   

[sprocket]

Just a added note put a shut off Valve in so the gas does not drain into your engine