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Trouble Spliting Crank Cases (Driving me Nuts)

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After my gearbox went yesterday I decided to tackle it and strip the gearbox, I cannot get the cases to split ,everything is out of the engine and the next stage is to split the cases , they have moved apart about 1/2" and will not move any more , the gap is even all the way round but its stuck fast ,the crankshaft seems to be stuck on the r/h main bearing and will not budge any ideas plz .....

Edited by wato

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After my gearbox went yesterday I decided to tackle it and strip the gearbox, I cannot get the cases to split ,everything is out of the engine and the next stage is to split the cases , they have moved apart about 1/2" and will not move any more , the gap is even all the way round but its stuck fast ,the crankshaft seems to be stuck on the r/h main bearing and will not budge any ideas plz .....

The bearings are pressed onto the crank. You need a case splitter (basically a steering wheel puller, but with 3 totally independent arms) to pull the cases apart.

If you have been beating on it or prying, your crank will need to be trued.

When you reassembly, make sure to do it with no force!

Best way to reassemble is as follows....

Start with right case half. Using a HOT steel slug (impact socket works quit well), heat the INNER race of the right crank bearing until the bearing doesn't spin. Use a pick to make sure it is heated well enough. Carefully (both quickly and deliberately) lower the crankshaft into the bearing till it is bottomed out. Bearing will cool and clamp onto the crank.

Now assemble the trans and everything in the right half of the case.

Set the whole assemble on the stand with the shafts pointing upward.

Now, heat all the bearings in the left half of the case in the same manner with first heated the right crank bearing (input shaft, output shaft, left crank bearing). Once they are all heated to the point they do not turn, CAREFULLY lower the left half onto the whole assembly in the right half. It should slip right together. If it does not, use the puller to disassemble and try again!

Once it is together and the bolts are tightened, the crank will not rotate. Use a brass hammer to tap each end of the crankshaft to set it in the bearings properly and all will be fine!

Assemble the rest and let it rip!

Make sure you do not overheat the bearings. Once they are just hot enough that they do not spin you have expanded them enough to overcome the interference fit between the crank and the bearings.

Hope this helps!

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case splitter.... great tool sold at RM... Most of the RMs have retainer clips for the crankbearings, So simply just driving the bearing out wont do.

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case splitter.... great tool sold at RM... Most of the RMs have retainer clips for the crankbearings, So simply just driving the bearing out wont do.

I know i can see the retainers down there , thats the frustrating thing its nearly split but just stopped coming apart , I thought once it came off the dowels it would fall apart little did i know lol.

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Pull the seal and hit the bearing up with a torch. You can also work on pulling the other side first if on side is stuck. Are you taping on the countershaft with a rubber mallet while splitting? Are you using a case splitter?

Good write up on reassembly above. Only thing I would add is I freeze the crank for at least 24hrs prior to assembly. Crank falls right into place this way.

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