Never seen this before

I was disassembling this Kz engine today. I removed the oil pan and found a bunch of Jb weld smeared all over the place but not crack on the pan. So I split the cases toady and found this. Looks like someone used a longer bolt on the right side lower mount and pushed the steel plug used to plug the drilled passage into the case cracking it. There was JB weld all over. I'll bring it to my welder and have him take a look. Im thinking of just using a 12mm aluminum rod plug and welding that in place instead of the steel plug. Some people should not work on anything. Im to far into this project to stop so its either fix this or buy a new set of cases. I finished removing the pieces that were ready to fall out and the steel plug is sitting on the edge

Three steps forward....two steps back.  I suspect that can be repaired but will require a lot of machine work.  ie: $$$.  It's the lower case so you might be able to use another lower case and preserve the engine serial number.

Hmmm..., so we add an inspection mirror and more powerful LED flashlight to our evaluation kit when inspecting a Z-bike for sale, so we can look up underneath the lower motor mount areas checking for damage.

It took some serious ham-handedness to force the bolt further into the case after to bolt's end contacted it.
( Huh...! Still some bolt left sticking out & it doesn't want to turn!?  I'll just grab my 1/2" impact driver & git 'er done! C'mere dude... hold muh beer.)

In Jr. High School shop class (remember shop class?) slmjim watched a Disney(!) movie about a character named 'Primitive Pete'.  Primitive Pete is a master at using the wrong tool for the job; a screwdriver for a chisel, slip joint pliers for loosening (chewing up) a tight nut, for instance.

EDIT: seems ol' Primitive Pete is still around.  Hasn't aged a bit.

WALT DISNEY 1945 INDUSTRIAL CARTOON "THE ABC OF HAND TOOLS"



Just like there's a huge difference between a  a 'motorcycle operator ' and a Rider , motorcycles seem to attract an overwhelming number of amateur 'tool operators' for some reason.  With the elimination of shop class in many schools, far too many young American men no longer acquire even the most rudimentary mechanical knowledge.

It'll be interesting to see if the case can be salvaged.

Good Ridin'
slmjim & Z1BEBE

I think it can be repaired. Should not require any machine work just weld up the hole to prevent oil pressure loss and leaking out through the case where the plug is at. Not worried about engine numbers as this was an engine(( in a hacked up chopper frame) I got with the purchase of a 1974 Z1. It was a two for one. The 74 was in good condition .

My goal with this engine was to throw it in a frame and use up some of the parts I had around but it not turning out that way. Still should one a fairly cheap (relatively ) build.

I think I have it solved by using a stepped plug which plugs the oil pump side (10mm) from spewing oil back into the case and on the outer one it is 12mm. I made them fit very snug put them in the freezer and used red Loctite. The plug sits maybe a 1/16 deep on the mount side and I covered that with JB weld. When it dries I may use a bit of JB weld around the exposed pin and the cracked out case. I think it will work just fine without welding any thing. the plug aint going anywhere. There is enough shoulder on the oil pump side and the outer portion of the bore to make a good seal.