Author Topic: Splitting the cases question  (Read 1514 times)

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Offline Cain74

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Splitting the cases question
« on: January 02, 2012, 03:06:54 PM »
I have looked at the diagrams in the manual and I am pretty sure I have all the top and bottom bolts removed.  Are there any hidden bolts that people usually miss?  I can't pull them apart.  The gasket has a good grip on them.  Is there a good technique in separating them?
(2) '73 750's Currently spread around the garage

Offline rbmgf7

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Re: Splitting the cases question
« Reply #1 on: January 02, 2012, 03:47:42 PM »
Well, if you are sure all the bolts are out I usually get a metal scraper and chisel it in an area where the cases have an offset. Try from the back of the case since the crank seals are usually in there tight making it more difficult to split from the front.

Offline NP3

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Re: Splitting the cases question
« Reply #2 on: January 03, 2012, 02:25:29 PM »
Once all the bolts are out, the cases should come apart relatively easy.  You may have to just bump one side lightly with a mallet to crack the seal, but don't force it.  If the cases are not coming apart you've most likely missed something.  An often overlooked bolt is inside the oil pan, so make sure this one is out.  Also, the shift linkage and points plate run across the two case halves, so those have to come off too before you attempt to split.  If you need more info. you can also search for "splitting case".  A good number of posts with helpful information will come up.
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Offline ekpent

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Re: Splitting the cases question
« Reply #3 on: January 03, 2012, 02:43:11 PM »
There is a certain amount of bolts that you should be able to count but I do not know that total number right now off the top of my head but I bet someone here who has done that recently knows--

Offline lucky

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Re: Splitting the cases question
« Reply #4 on: January 03, 2012, 03:13:20 PM »
I have looked at the diagrams in the manual and I am pretty sure I have all the top and bottom bolts removed.  Are there any hidden bolts that people usually miss?  I can't pull them apart.  The gasket has a good grip on them.  Is there a good technique in separating them?
You looked at the diagrams in the manual, but did you follow the instructions?
I would go back through one more time and you may see what you skipped.

Sometimes the manual has mistakes too.

Offline MCRider

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Re: Splitting the cases question
« Reply #5 on: January 03, 2012, 03:17:08 PM »
I have looked at the diagrams in the manual and I am pretty sure I have all the top and bottom bolts removed.  Are there any hidden bolts that people usually miss?  I can't pull them apart.  The gasket has a good grip on them.  Is there a good technique in separating them?
Strictly speaking, there is no gasket. just a very light sealer, which should loosen up with some heat from a heat gun, maybe a hair dryer.

There are 2 screws in the drive sprocket area. There is one hidden under the electric starter cover. The rest are pretty obvious.

I use a very small chisel in the rear of the engine, there is a flat spot, you can slide the chisel into the seam. A few gentle taps and you should hear the tone change as the cases let go. Do not force it.
« Last Edit: January 03, 2012, 03:19:38 PM by MCRider »
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Offline ealanm

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Re: Splitting the cases question
« Reply #6 on: January 03, 2012, 04:51:40 PM »
I would avoid the chisels.  I use a plastic hammer, and plastic paint scrapers if I feel the need to wedge. 

Tap around the perimeter of the joint with the plastic hammer and listen carefully to the sound.  When the gap starts to move the sound will turn slightly hollow-sounding.  If you look carefully you may see some movement.  Once you can clearly see movement, lightly tap in a plastic scraper at that point and then keep working your way around.  It takes a few minutes, but eventually the whole things pops free, without having to put any significant strain on the casting.

On the CB750 case I just split, the trickiest bit was that the seal on the final shaft was stuck to both cases halves with silicone.  I had the whole thing free and moving but it wouldn't come off easily.  It took me a couple of minutes to figure that out.
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