Splitting cases. No matter how hard I pull...

Crashfangio · Post by **Crashfangio** » Wed May 13, 2009 5:33 pm

Hi. I'm in the process of pulling down my '73 750GT motor. The cases have never been parted (lock wire intact). The reason why I am doing this is more about preventitive maintenance, as the machine was sitting idle with the barrels removed for about 15 years prior to me finding it.

The problem that I am having is that the damn cases will not budge apart one bit. Now, before anyone asks me to check, yes I have removed ALL bolts.

Can anyone tell me a reliable method to split the cases?

cafe*racer · Post by **cafe*racer** » Wed May 13, 2009 10:45 pm

I swore I had removed all the bolts in my cases too... There is one bolt that has a threaded stud sticking out of a hex head, does not look like any of the other allen headed engine bolts. You will need a deep socket to get it out. Should be sticking out of a recess of the left side below the cover, I believe it is for attaching side mount kick stand. The cases should practically fall apart if this is in fact the problem. You will kick yourself if this is it, just don't pay for the lesson like I had too.

Crashfangio · Post by **Crashfangio** » Thu May 14, 2009 2:39 am

Yep, I've already removed that one. I'm absolutely confident (famous last words..!!) that I've removed all the bolts.

I've looked at the parts catalogue and confirmed that we are talking about the same bolt. For your own interest, mine doesn't have the extended threaded stud, it is just a plain standard cap screw style head (Australian delivery GT's didn't have a side stand as standard as far as I'm aware, just the centre stand).

Nup, she is stuck fast. I just wonder is it possible that the mains bearings may be binding tight on the crank main shaft??

Help!! I'm open to any suggestions that don't involve butchering the case mating surfaces.

nottonight68 · Post by **nottonight68** » Thu May 14, 2009 2:51 am

i presume you've rotated the kick start shaft

Crashfangio · Post by **Crashfangio** » Thu May 14, 2009 4:15 am

Not yet. From what I can tell I'm at the step prior to having to do this.

The manual indicates that after initially parting the cases, rotate the kick start 45deg. to release it from it's stop. I interpreted this as being done after the surfaces are beginning to separtate, but before the uppermost case can be completely removed.

Anyway, just to say I've tried, I have just fitted the kickstart and rotated it while attempting to separate the cases and still no luck.

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wdietz186 · Post by **wdietz186** » Thu May 14, 2009 6:19 am

If it has been sitting with the jugs off and in a dampish environment it may have corroded the locating dowels in the cases. You can try soaking the bolt holes and the joint areas with penetrating oil and tapping firmly with a softish hammer. The idea is to get the cases vibrating and break the seal.Heat will help too.There is usually enough slop in the bearings that you will get a small separation even if the races are sticking on the shafts.

Post by **BevHevSteve** » Thu May 14, 2009 7:12 am

I seem to remember 2 things..... The kickstart at 45 deg part and before that some hidden snap ring that must be removed......?

I think....

Crashfangio · Post by **Crashfangio** » Thu May 14, 2009 7:43 pm

And 1st prize goes to....wdeitz186!!

I soaked the entire joint with WD-40 and also sprayed a heap inside the bolt holes and just began giving it a good old fashioned manned-handle. After a while I could see bubbles forming between the joints as I continued working it. I knew the battle was won at that point!! A bit more spray and a tap with the rubber mallet and open she goes.

The surface doesn't appear corroded as such, just 30-odd years spent clamped together taking its toll.

Cheers guys!!!

Per Garbos · Post by **Per Garbos** » Sat May 16, 2009 8:03 am

I have a widecase and it was also impossible to split the cases.
I really tryed everything, and finally I had to make tread in the through-going mounting holes (engine/frame)

With 2 bolts, one in each side, and a distance pinn between, it works like a puller.

I made a set for all four mounting holes.

The tread length was only 6 -10 mm and the tread was not very deep...I used M12 for Ø11 holes.

Not an ideal solution, but still better than a screwdriver between the parting line.

Best regards Per

Crashfangio · Post by **Crashfangio** » Sun May 17, 2009 5:58 am

That sure sounds like an innovitive way to seperate the suckers, Per. I'm glad I didn't have to go to those lengths.

DesmoDog · Post by **DesmoDog** » Tue May 26, 2009 3:21 pm

Moot point now I suppose, but FWIW - WD40 is not a very good penetrating oil (nor is it intended to be). A true penetrating oil or a 50/50 mix of acetone and ATF will work much better.

Lumpy · Post by **Lumpy** » Wed May 27, 2009 10:58 am

Used to be a red fluid around many moons ago called penetrene. Don`t know if it`s still out there but it was a great penetrant for those types of applications. I have heard that diesel fuel is a very good penetrant also.

bobnorton · Post by **bobnorton** » Thu May 28, 2009 1:49 am

I remember watching Vic Camps Mechanic splitting a case in the paddock with no special tools ,the trick was to work really fast before the cases cooled off and gripped the bearings, so perhaps heating the cases up would help??