Torn reduction gear hole

So last night while changing the starter, I noticed the reduction gear shaft hole is torn out. I haven't broken down the engine far enough to see if this housing is replaceable, or if it is a permanent part of the block. Can anyone tell me what my options are here? I'm guessing if the housing is not replaceable, then I'll have to get a machine shop to weld it up and put in a sleeve?

To partially answer my own question, I finally found a diagram of the crankcase showing that this is indeed part of the engine and not just simply a shroud... So :sick:

Guess the next step is checking local shops and try to get an idea of how much it will cost (or if its even possible) to get this welded, and determine if its going to be worth the money. Ugh I'm not happy about this. Definitely not off to a good start on this bike.

[UPDATE] After making some calls, it sounds like it could be horribly expensive to get the case properly welded and annealed, however I have found crankcases listed on ebay for surprisingly low prices... In some cases there is no indication of the particular model the block comes from. If I get a crankcase that is listed as the same year and size (1981 KZ1000), and ensure it is a 998 like mine, is there anything else I would need to look for before ordering? Can I simply grab a new case and have the local engine shop fit it for new bearings, then drop in everything else from my old engine?

Not sure about your motor as all my stuff is pre-80....but if you get a set of cases off e-bay make sure you get the main crank bearing cap from that specific motor as they are not interchangeable. They are line bored the same way that cam caps are and you cannot mix and match. What also happens in my motor is all the bearings are fitted to either the crank or gearbox input and output shafts so I don't need to get bearings set into my block as you have mentioned...I don't know if that is the same with J motors.

Another idea....I don't know how much stress that torn part is under but could you perhaps fix it yourself with JB Weld? That stuff is pretty amazing!

Thanks for the info... I asked the seller of the case I was looking at, and they did NOT have the bearing cap still with the case. In fact, none of the crank cases I am finding appear to have that piece included with them, and there are several of the caps for sale individually. Perhaps its just a matter of an engine shop re-grinding the pieces to match?

By the way, the seller also mentioned that there is no CC size mark on the front of their case. Is that common? Does it even matter in the crank case if I get one made for a 998 or 1015, as long as it was made since 1981? I've seen a lot of police bike parts for sale, part# 14001-5042. My engine is listed as part# 14001-5096 or -5098... Does anyone have a cross-reference that tell if I could use the police case to rebuild my engine?

I have a 1981 kz 1000 j complete bottom end if your intrested. It came from a barn find that i pulled the head to use on my bike then sold the piston and jugs. I didnt see any problems with it when i pulled the jug and pistons.

I think I may have found a match... The manual lists 14001-5096 as my case, and I found one online with part# 14001-5099 (1982 police engine). Comparing the parts lists, both models seem to have exactly the same parts listed to install in each, and the only difference I see is the color (black vs silver). Before I buy, can anyone else confirm if this looks suitable?

Well you should post your bikes year and model. Go back to your user profile,and put your bike details in the signature. That way it shows up for past and future posts.
Your picture looks like a J engine case. The Police bike case would fit correctly.

Ack! I've been looking for where I could put in my details, guess I just missed it. Info is entered now, and you are correct -- it is a KZ1000-J1.

@Powerstroke_fan: Thanks for the offer, but for now I'm going to take my chances and hope for the best. Honestly if the inside of the engine turns out to be in bad shape, I need to cut my losses and find another bike to start with.

Not necessary to get a whole new bike....just a motor, if you find more problems than just the torn piece you know about. It is really a bad thing that the motor cases you see on e-bay have no crank cap and that there are caps for sale separately, there is no way to have a machine shop make another one as far as I know, it's just as (if not more so) important as the cam caps as I mentioned earlier. Do not be fooled by that one. Good luck man.

Edit: The cc size is always found cast on the cylinders and not the bottom end.

There were two different cases I found listed, both by salvage yards, and both responded back to me that the cap was not included. I also found other cases with pictures showing that the cap had been removed and was not included. So I guess that's how we tell who knows what they are doing when they resell the parts.

In the meantime, I found a few others listed which plainly showed the cap included. The one I just purchased is from an '82 police bike, includes the cap, and already has a black paint job on it (one of the things I was planning on doing anyway).

Since I'm not familiar with the assembly, I am not certain but it looks like the bearings are press-fit into each half of the crank journals already? Since I'll be using my old crank in a new case, I would assume I need to toss the bearings and get new ones to properly break in? Or is there a chance the parts will fit together properly? Eesh, time to do some serious reading and bone-up on rebuild procedures for this engine. At this point the only thing I know for certain is that I'll be needing a new gasket kit.

Not to throw a monkey-wrench into the conversation, but couldn't this be adequately repaired by fitting a large steel washer over the outside of the material that surrounds the hole, and pinning it to the webbing. I'd also machine into the webbing just-enough to create a pocket for the washer to fit tightly inside of, and create a flat surface behind it.
Then fill the crevice with the JB Weld, or put a sleeve in.

You could be riding again before the sun goes down.

You wont need to buy new bearings unless there wore or bad. and you will need some three bond or yahama bond to seal the case halves together.