Strange Hole in Crankcase

I've got a hole in my crankcase just where the left side cover mates with the block. It looks like it could be a factory cut but I can't figure out why the manufacturer would put a hole in this location, especially since it's a prime spot for collecting water. No dice when I look through the manual and forums.

Anybody know what this is?

Has a PO messed something up here? Please say no...

Tried to take a better closeup but the camera is acting up.










{Edit} Bike is a 1980 KZ1000 G1 Z1 Classic.

Hard to tell but it could be put there to drain water as the part of the upper crankcase is like a basin of sorts. I haven't paid attention to that spot on my bikes in some time but can take a look tomorrow to compare.

Later, Doug

Doesn't look right to me, has a chain gone awol and knocked a chunk out of it? What is it like under the chain cover, epoxy or welding there will tell a story...

My Z1 has it too. Just lower. It's a drain hole.
Steve

Looked at some cases for sale on eBay. Appears that hole is common on 73-80 900/1000's. I think it is for draining water or leaking fuel from the top of the cases.

I took these pics from two different auctions.



Later, Doug

I thought it looked strange also but I just looked at my 77KZ1k engine and there is a similar hole. Your inside hole looks misshaped but there is a drain hole in that area.




Jim

Interesting, I never knew that. Seems like an idea that got dropped in the later models.

Ok, good to hear! I was worried for a minute. Didn't notice the hole until I started cleaning up the air box and my heart sank.

So seeing how this appears to be a drain of some sort, any ideas where fluid could drain to from this point? I haven't found another drain hole in the side cover....trying to avoid pulling it off if it's not necessary. Water/fuel buildup in that side cover doesn't sound good, so it's gotta go somewhere, right?

It's open on the bottom. Do you have a manual?
Steve

Who knew? ..... my 80 MKII doesn't have the cut out or hole. Just goes to show, we haven't seen it all and new can be found.

This is a pretty interesting thread I must say. I thought it might be an auto oiler for the chain at first but it's nowhere near that. Perhaps for ventilation cooling? Maybe it was for some super-rare accessory, or for an accessory that was never put into production.