crankcase interchangeability

hi all - I have broken off the upper crankcase lug which bolts to the barrels at the front there are several available in the USA. Mine is a uk model xj650 4KO 19980 not sure if they are the same as seca USA around this date?

 

All XJ650 and XJ750 (aircooled) engine cases are the same castings. Ideally you will want to get a matched set. It may be less expensive to have the lug welded, or built up with weld and a new hole tapped.

 

Thanks - I seem to have misplaced the broken off lug so building up a lug would be an option if I ca find someone to do it. I have seen a top crankcase in the UK, may be a risk?

 

If you have to use just half of a set, you'll need to go through the process of finding out what crank bearing shells you have, what shells the top half of the replacement crankcase has, and what bearings you will need in the upper half to keep clearances in spec. It's not something to be rushed.
The bearing info is electro-etched into the rear of the crankcases, and the crankshaft bearing journal info is inked onto the end of the crankshaft. The bearing shells have bits of (likely faded) identifying color on one edge, near the top of the arc.

 

Pages 7-12:

http://www.xj4ever.com/catalog/frame-engine-id.pdf

 

My new keyboard arrives next week. All of the keys will wok again

 

Thanks k-moe, just ordered a pair of cases from a us breaker, decent price. Started on the cyl head, cleaning crud off, one of the many non-glamorous parts of restoration. Fortunately I have learnt to take it steady and try to enjoy and not rush it. I appreciate the time you guys give up to us newbies to the xj, I will have a browse on you tube to watch some xj action to keep me going till the big day mine fires up.......

 

You will still need to figure out which bearings you need in order to put the crank ino the replacement cases, but the job will be a bit less math intensive with a matched set. You might even get lucky (as I did) and get the bearings you need already in the new cases. I only had to swap a few bearings over, and they plastigauged in spec.

 

Snap! I did exactly the same thing! Just collecting NOS parts here and there for a rebuild.

 

Whitby eh? The home of Fish and Chips, Jet and Dracula - nice! Hope you get the motor sorted those N Yorks moor roads will be a blast.