Splitting the crankcase

Hey guys, I'd thought I'd share the technique that worked for me in splitting the cases, in the hopes of helping someone with their project. The engine had been taken apart in the past and there was a healthy amount of Yamabond or similar holding the cases together. I didn't read anything about having the engine upside down before I did this and I'm sure I did some other cringe-worthy things in the process (including leaving the stator on while splitting, which doesn't seem to have hurt anything, fingers crossed).

I cut a 12' piece of 2x4 in half and drilled holes to attach them to the sides of the engine, using two of the engine mount locations and a few feet of threaded rod. Then I slipped the short end under the lower beam of my engine hoist, leaving the longer lengths of wood to provide leverage on the other side. I used a 1" jack handle to lock that end down. Then I slowly pulled the engine up with the hoist until the case popped open, pretty darn evenly. The materials cost about $20 but there's a good chance I'll use them again someday.


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Hey guys, I'd thought I'd share the technique that worked for me in splitting the cases, in the hopes of helping someone with their project. The engine had been taken apart in the past and there was a healthy amount of Yamabond or similar holding the cases together. I didn't read anything about having the engine upside down before I did this and I'm sure I did some other cringe-worthy things in the process (including leaving the stator on while splitting, which doesn't seem to have hurt anything, fingers crossed).

I cut a 12' piece of 2x4 in half and drilled holes to attach them to the sides of the engine, using two of the engine mount locations and a few feet of threaded rod. Then I slipped the short end under the lower beam of my engine hoist, leaving the longer lengths of wood to provide leverage on the other side. I used a 1" jack handle to lock that end down. Then I slowly pulled the engine up with the hoist until the case popped open, pretty darn evenly. The materials cost about $20 but there's a good chance I'll use them again someday.


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CAN THE DRIVE CHAIN BE TAKEN OUT OF THE PROCESS WITH YOUR CHERRY PICKER METHOD TO PROTECT THE ENGINE SURFACES?
 
Heat really makes a difference, 10 minutes with a heat gun around the rear seam and it lets go pretty easy. Anytime you have a large mating surface like this; if you get one end to spread a bit, put in putty knives or other thin blades as far forward as you can, then push, squeeze, clamp, the open area closed, that levers the other end open, done. It's kind of funny really, you are mainly worried about leaking when the engine is hot????.......... guess it's the elastic that counts, not adhesive strength.
 
Here's what I plan to try. With the motor upside down in my "flipper" stand, I'll put one of those normal bottom stands back on. Then, I'll cut a length of plate to attach to it (yellow line). Then I'll place a bottle jack under it at the front, between it and the front mount on the "flipper" .....

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A couple pumps on the bottle jack and I think the cases should come right apart, at least at the front. A couple good raps with a big rubber mallet on the portion of plate that hangs off the back I'm hoping will separate the seam at the rear.
 
5T I somehow envision a 20x50 foot shed with racking full of "iron works"
That one covers effective and elegant but leaves out simple.........
 
Well, if you have the ability to cut and fabricate steel, it's not a very difficult task. I plan on using a length of big heavy 3" x 4" or 4" x 6" angle with the "up" leg cut mostly off. I'll leave maybe an inch of that leg on there to stiffen the remaining "plate" against bending when I jack up on it. Not that it would anyway. I don't think these cases are stuck together hard enough that jacking them apart would bend 1/4" steel, lol.

Oh, I only wish I had a shed that big, lol. Nope, I'm just a very small time home tinkerer and fabricator. I only have a 16' x 16' shed in my backyard. But, I still manage to whip up some pretty neat stuff. I just finished modding up a HF motorcycle tire changer for my buddy. I'll have to get some pics. Instead of mounting it on top of the floor mounted HF small car tire changer, we're going to put it on the front corner of his HF motorcycle lift table. It will be quick attach/detach so he only needs to put it on there when he wants to use it.
 
I read this thread, and others that I could find on splitting cases. This is what I did. The motor I acquired was mounted on this automotive engine stand, I kept it right side up, passed a ratchet strap through the top rear motor mount and a anchor I fastened to my garage ceiling. I lifted the engine stand up so that the weight of the motor was on the ratchet strap, only about an inch off the ground. I used my heat gun and heated the seam where the two halves join, probably for about 20 minutes. I pressed down on the engine stand and the two halves popped apart. Now I have it rotated over and am debating to lift the bottom off or what to do next. On to more uncharted territory for me.
 

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Went through the hole thread and it was a huge help. In my case I adapted a wooden stand I already had. I bolted the top of the motor to it and added some weight to the base. Then made a simple connection to the lower case and hung the whole thing from a rafter with a come along a couple inches off the floor. About 15 minutes later gravity did the rest and they came apart. Hope it helps someone in the future.
 
i just started rebuilding the engine for my DualSport/scrambler project and this is what I came up with for splitting the cases. I went to Ace and bought four 8mm extended nuts, screwed them partially on to the studs, screwed the longer case bolts in until they bottomed on the studs and tapped the bolts until the cases started to split. When there was enough of a gap I used my pry bars to continue splitting the cases until I could lift the top from the bottom. I did use my heat gun to warm the seam as best I could before starting the process. I hope this helps someone,
 

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