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How to safely remove crank shaft bearings from your dirt bike.

I had a customer ask how to remove his crank bearings from his crank shaft.
Since he is in New Zealand and I am in Eugene, OR USA I took several pics.
I figured there may be others on this site wondering how to do this so I thought I would post them.
I use a Crank Bearing Puller from K&L 35-9603
There are many different types of tools that do the same thing and at a variety of prices.
This kit is about 100 USD.

As you can see, this is a typical problem


The first thing I did was to lubricate all the threads on the tool to make sure they operated smoothly with no galling.
Then I opened the jaws of the puller and slipped it around the first bearing.

I then tighten the nuts by hand until they are snug and even.
I use a wrench, not a impact gun as you can't feel as much with the impact gun and you could damage the tool or the crank shaft.
I tighten it so that the two halves are snug but not to the point where the inner part of the jaws are touching the bearing journal.

Next, I install the bolts that hold the cross piece.
I only install them finger tight but I make sure they are nearly bottom out.

Then I install the cross piece and tighten the long bolt finger tight so that it is snug against the end of the shaft.
If your crank has an internal thread on the end where the long bolt is pressing I recommend that you put a bolt in the end of the crank to protect the threads from damage.

To finish, use a wrench, not an impact gun to pull the bearing off.

It should slide off fairly easy as most of the time I can hold the crank in one hand and turn the wrench with the other.
Repeat on the other side if required.

Piece of cake..... But, I'm not done.
Internal engine parts are easily corroded in the Pacific Northwest.
As a quick and easy preventive we spray them with some chain wax.
In the past we used WD-40 but it does not last long enough.

When we are done they have a nice coating like this

That's it.
With the right tools it takes about 10 minutes to remove both sides and put the tools away.

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This page last modified: Wednesday, 25-Apr-2012 16:54:55 PDT

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