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How to Safely split your Engine Cases.
Here is a problem that veteran engine guys will laugh about.
However, for the uninitiated, this can be an intimidating situation.
You need to replace your crank shaft.
So, you have removed your engine from your bike.
You have removed all the bolts, springs, snap rings, cylinder, linkage, ect from your engine.
Here is what your are left with.
If you have access to a digital camera, take a lot of pictures as you go.
If you don't have a digital camera, you can always make rough sketches.
Remember, it's better to spend a little more time to start with then spending a whole lot of time and money later :-)
Also, note that the case bolts are different sizes and you need to be sure they go into the correct holes upon re-assembly.
For this demonstration, I used a 93 KX500 Engine.
Some guys will grab a hammer and start beating the transmission shafts to split the cases.
While this can in some situations work, you always take the chance of damaging your shafts, cases, gears, ect.
The solution is to buy, beg, or borrow a engine case splitter.
This one is a Motion Pro but there are many on the market that work just the same.
#1 rule. DO NOT BE IN A HURRY.
Engine cases and transmission parts are expensive and can easily be broken.
Before you get started, take the time to clean the threaded areas from your cases carefully and even run a test bolt or chase the threads with the correct size tap if required.
Oil all the threaded rods, set nuts, and threaded holes.
Next, assemble your tool.
Slip the arms onto the main shaft.
Then hand tighten the set nut.
Next, slip on the centering tool on the end of the shaft.
Then run the threaded rods through the arms with the retaining washers and set nuts.
Try to spread them out as evenly as possible so that you get even pulling pressure on the cases.
Hand tighten all the set nuts so that the center axis of the pulling tool shaft is in line with the center axis of the crank.
I know it's tempting to use a ratchet or a impact gun but please, resist the temptation and use a hand wrench.
Yes, it takes a bit longer but your tool will last longer and you will not be as apt to strip the threads in your cases.
All ready to go?
STOP!!!!!
Make sure all the engine case bolts are removed.
If even one of the case bolts is in, you won't be able to split the cases.
Once the bolts are snug and the axis of the puller is properly aligned with the crank, start tightening the main puller shaft bolt.
Within a half to a full turn you will usually hear the cases pop.
Check the back of your case to make sure it is not pinching at the back while split in the front of the cases.
If that happens you may need to loosen all the bolts and move them around to get more pulling power on one end of the cases over the other.
Sometimes no matter how you position the bolts the back of the cases will hang up.
If this happens, you may need to take a rubber mallet or dead blow hammer and lightly tap the output transmission shaft.
Once again, do not be in a hurry and don't tap any harder then is absolutely necessary.
All done.
Usually it takes me about 10 minutes to pull all the tools out, split the cases and put the tools away.
Piece of cake!
This page last modified: Thursday, 09-Aug-2012 22:51:39 PDT
