CR360 crankshaft repair in situ'...flywheel nut sheared off

I recently bought a 1976 CR360 compete engine in unknown condition.

I took the head off to view the state of the piston and bore and was surprised to see a freshly bored cylinder with honing marks and a brand new piston. I don't think the engine had ever been started.

The reason why it hadn't been started was that the flywheel nut and c/shaft thread were missing. The end of the crankshaft had been sheared off. The engine wasn't seized and I can only guess someone had tried to undo the nut the wrong way, which was left-hand thread! and it sheared off.

I pulled the flywheel off and took the whole engine to a machine shop. I removed the clutch cover and they were able to take a reference point from the machined face of the LHS crankcase half and mount it on the table of a milling machine. Cylinder head and barrel were still in place.

They then drilled and tapped the crankshaft and made (from 12.9 class bolt) a M12x1.0 left hand thread stud which was thread-locked into the crankshaft. Next, a nut was machined from the same 12.9 class material.

Job done.........

I thought I'd share this tip to show that it isn't necessary to strip the engine to have this type of repair made.

I hope it helps someone somewhere..........

Andy

final photo.....

That's awesome

where there is a will there is a way.....where there is a purchase price..there will be a fix..nice work

I had a 360 with the same previous owner. The stud was broken off. I duct taped the rod to the crank in its lowest position. I chucked the crank in a lathe and turned the nub that was left flush to the taper. Then I center drilled it, the drilled and taped it for a set screw. I used the forever loctite on the longer set screw and installed it. Then I turned it down to the proper length. She’s running today.

This engine was butchered too. They turned the sleeve that was stuck up for the head to seal flush with the fins. Then they turned the head the sameway. They used a piece of header gasket asbestos for a head gasket. Luckily I had an extrat cylinder and head. I have no clue as to what they were thinking.

Saving one husky bike at a time.