Cracked engine cases

So, once again I’ve proven to myself that I’m a complete idiot. Whilst separating the cases on my Z1R engine, I surmised that they weren’t coming apart easily because of corrosion around the dowel pins, hence it was going to be simply a case of tightening down the three bolts more. Wrong. Oh so very wrong. I missed the bolt in the starter motor cavity, and as a result I now have a cracked lower crankcase … 

My own stupid fault quite obviously, but now I need to try and remedy it. I was originally looking to weld them up, but I’m now thinking that JB Weld should do the trick as I don’t believe it’s in an overly stressed area, and we are talking one of the 6mm bolts. However, the stress has distorted the area slightly, such that it’ll need to be pushed back into shape before trying to fix it.

Thinking that if I bolt the cases back together and then heat the area with a heat gun, the material should ‘soften’ enough to return to it’s original shape. Then I apply the JB Weld, let it set, and see how the cases look when I unbolt them. Wondering what the consensus is on this, am I naive in thinking the heat gun will heat the area enough for this to work and that JB Weld will hold, and do I just need to bite the bullet and get it welded ? Alternatively, it is going to be simpler to just buy another set of cases ?

For background, this will be a mostly-stock engine rebuild, and as its going into a Mk II chassis, originality re Z1R engine number is irrelevant to me. At the moment, I’m thoroughly discouraged with this build, and on the verge of putting the MK II aside to start on a GPz900R project waiting in the wings. I’m hoping for a cost-effective solution, to restore some enthusiasm !

Thanks in advance,
Brian

Dont mess around :ohmy: Get someone who knows what they are doing to Tig Weld it

^^^^^^^^^^ + 1

+2

As stated leave it to a professional. A heat gun will do nothing for it at all.

If all else fails, Call or e mail Joe Hooper at Pit stop. He advertises here and Im sure he can help you. I have had very good luck with his company for quality work and pricing
HTH
Dave

get it tig welded by a good competent welder :dry:

DO NOT use JB weld, TIG it. I know it's the most difficult and expensive method but when it is done it wil lbe done for good. JB wled has it's purposes but in this case it would be a ghetto repair.

I disagree - JB Weld would be the most expensive repair.

It will look like it's working, then will fail, dumping your engine oil, probably at speed. If you get lucky and none of the oil pouring out of your engine gets on your tires, you'll seize a cam bearing, score a rod bearing, score your piston sleeves. burn out your rings, and probably cook the crank. After that, you'll still have to TIG weld it to fix it, but now you have to replace other engine components as well. The cheapest solution is to just fo it right the first time.

i made that same mistake once :sick: !
you will never forget that bolt again :whistle: .
i tigged it up and filed it back flat and it hasn't been an issue.

leon

If you aren't worried about the case numbers, buy another set of cases. Probably cheaper than welding the cases you have.

Cynjut wrote: .....you'll still have to TIG weld it to fix it........ The cheapest solution is to just do it right the first time.

+1 Absolutely true! Ed