welding a crankcase?

hi all.
i'm in the process of renovating a spare engine i have for a xj600 "pre diversion" . unfortunately one of the bottom engine mounting bolts has been broken off, " through to inside". then it had been stuck on with e-metal and some clamps made to bolt it back on. I split the cases, taking bottom off only , and took the bottom half to an aluminium welders, they were reluctant to take the job on, due to the amount of work needed and could possibly charge me £100 gbp .
ive seen a pair of empty crank cases on ebay for £40, with the top half pretty much toast.
so my question is, is it possible to change just the bottom half of the crankcase, using my original "shells", without the need for plasigauge etc
thanks , heres hopping
stu.

 

sorry , should have read "mounting bolt lugs"

 

No. They are machined as a dowelled pair. So you need a pair of cases. Even then, you will need to go through the various clearances set by the case dimensions at the factory - main bearing and thrust? being the main ones, not sure about the gearbox on that one.
Much easier to get it tigged. Keep looking, I know of a guy on another forum who does bike cases - should I ask?
It might well be £100 though...

 

Stu, sounds' like you need to make a trip down here (Bedford) and pick up one of my spare 600 bottom ends ( with that generator included).. Cheers

James

 

yeh, that would'nt be a problem, but acording to "Minimutly" , i cant just swop the bottom half


ah, just re-read that , i guess you mean the complete bottom end, to swop my barrels and head to.
trouble is a gasket set is around 100 quid

 

Here is a new set. Never heard of eBid before.

https://www.ebid.net/uk/for-sale/ya...hrSIZhjzcWHeOpTJOd3dzRydoWux9MmIaAhWyEALw_wcB

 

wow, no i've never heard of ebid either. why would someone have brand new crankcases for a almost 40 year old bike?
good score though "Franz", but i would still have to go down the "shells" route, plus a gasket set.
i've decided to repair it myself, after asking 2 different alloy welders, who wouldnt take it on. they advised using a strong epoxy , and refitting the clamps that the p.o. fitted
i'll let you know how i get on, i'll put some photos on when i get some

 

Why didn’t they want to take it on? Was it manky and covered in oil? Did you explain it would come to them stripped of paint and fresh from the dishwasher? Clean it and post some pics. If it’s clean and weldable I would take it on, but wouldn’t guarantee the cost without seeing it in front of me.

 

Definately better welded Stu in view of the cost as you say.

 

no it wasnt , i spent all day cleaning the bottom half, and ground away the existing jb weld ,or whatever it was, flattened the crack off ready, but of course there was still some of the old adhesive left in the crack, they both said "they didn't want the responsibility of damaging it. anyway sod it "and them", i'll have a go myself, cant make it any worse

 

Be careful welding cracks, preheat the aluminum.

 

Yes you can...

 

-----------------------------------------------------------------------------------------------------------------------------------
Be careful welding cracks, preheat the aluminum.
---------------------------------------------------------------------------------------------------------------------------------
Yes you can...
-------------------------------------------------------------------------------------------------------------------------------------
i'm only going to use the epoxy putty, jb weld stuff , not welding, ill se how it goes

 

JB weld and putty fine for filling holes but for anything that require shear-strength I'd say forget it' - try a few more places before squirting that muck in there is my advice.

 

Welding is your only option. Oil contamination is the reason welders shy away. You have not found the right welder yet. Good luck

 

So, how many people will you ignore before understanding this?
Get it welded.

 

ok, ok, i get it ,
i'm on with it -- i hope