Kz900 Engine casing crack after slight explosion. No clutch activity now.

Be nice if the original poster stopped by again to provide more info and clear this up

Very interesting. All I can add is that I have personally seen the same thing happen while I was riding next to my friend's 80 LTD1000. His countershaft sprocket cover made a loud noise and broke - out of nowhere! No work had been done on it recently and everything was working fine until that point. We changed the cover and it has been fine for many years since.

He did have the Red heavy duty clutch springs installed, and that puts a lot of extra stress on those covers through the push rod and actuator. Maybe a weak/stressed/damaged cover just can't take it and breaks. No mystery, sh#t happens! I think they even have bumper stickers like that!

I was so interested to read this because his cover has been the only one I've personally known of - now there's two. Anyone else have this happen??

79MKII wrote:

I was so interested to read this because his cover has been the only one I've personally known of - now there's two. Anyone else have this happen??

The count is now three, "Jack" told of how it happened to him earlier in the post.

I tested a clutch that had the countershaft cover fitted loosely and held by a single screw. The pusher actually flexed the cover since it wasn't held securely and I recall thinking it would break if I continued. If bolts are missing, the stress has to go somewhere when the pusher is worked. The double whammy in this situation is the two long bolts.. the one on the front top and front bottom of the cover. They are 110mm and often missing or broken.

Hi everyone. Sorry I havent updated in a while. Its been a very crazy past few days.You see I live in New york city, The Bronx to be more exact and my bike broke down in Queens. Now geographically these two areas aren't that far apart, but by utilizing public transportation....wooo!It takes me more than two hours to get from my home to where the bike was. This left me with very little time to do anything with it. And after work?Forget about it. It was pitch dark whenever I arrived. So two days ago my uncle and I rented a Uhaul van to move the bike. Bit of advice, I dont highly recommend anyone does the same. The Kz900 is one heavy bike! My uncle and I thought" we'll just get a couple of guys to help us lift it up into the back..." no way. Lucky for us the Uhaul place had a broken/detached ramp from one of there big moving trucks and they let us use it. Even the it was still difficult. Anyhow I have the bike home now. Ok I got the cover off:






From what I saw it didnt seem like anything big was broken. The sprocket was still in place and the chain too.The kick start still wasnt functioning though. I pulled the little rod that that mechanism thats connected to the clutch cable contacts. Pushed it in too.Nothing. It was really tough to do also. Anyway I noticed when I pushed the kickstart down that little rod spun. Whats supposed to happen? Is it connected to the cluch pushing thing? My rod had thoughts like that popping into my head, because of the way it looked:



Are they supposed to be connected? does that little pad stop it from spinning and allows the engine to start? I also thought this because I couldnt see how else that rod would come back to its original position after being pushed in, theres no spring or anything, at least it doesnt seem like it. Now theres the sprocket cover/pushing mechanism:






Does every thing seem to be ok with that? Anything missing? I cant seem to understand how that little pad would both push and pull the changing rod. I ordered a replacement clutch cable online and a replacement cover from oldkawman.com. Just waiting to get an email saying when he'll send it.
Also I found out why there were no bolts in the bottom of the cover: A bolt had been broken of in each one already! I can see broken ends in both holes. How can i get that otu? Or still find a suitable way to fasten it? will update again soon.

I think I have already pointed out that the broken off bolts allowed the clutch cover to flex and then break. To remove them depends on how much you have sticking out of the hole. If you can get vise grips on them, that is one way, if there is enough, you can cut a slot and use a flat bladed screw driver. If there is enough, you could weld another bolt to the broken off bolt and turn it out using the welded on bolt. If the bolt is broken off fairly flush, you could try using an extraction tool. Get a square-type extraction tool not an EZ out! The EZ will most likely break and you will have REAL problems as they are much harder than the bolt. You drill a pilot hole in the bolt and tap the extraction tool in the hole. It has an edge on the four corners that dig into the bolt and get tighter the more you turn it counter-clockwise. If there is no movement, don't try and force the bolt.

The last and probably the most realistic way of fixing the problem is to drill the bolt out. You will note that this is an M6 bolt with 1.0 pitch. You will likely need to find a VERY LONG drill bit since I wouldn't think you could get the drill back to where the bolts are without interference. Try a good tool store for this type bit. If you can find one, use a 1/4" very long drill bit which are pretty common. When you go to use a new bolt, go to a bolt specialty store and they will have 1/4" in the correct length. I have used 1/4" when I couldn't get the correct M6 bolt. You will need to tap the 6mm hole with a 1/4" tap but there is just enough metal left for this purpose.

Nahman- you'll need a clutch pushrod as well from the looks of
the one in your pics. And possibly a new pusher and ball
bearing-I'd be pulling the clutch to check.
BTW ,no clutch = no kickstart.

IMHO, it is almost impossible to drill out/ tap/helicoil those
cover mounting holes with the engine in the frame.

Is it me or does the pushrod look threaded. I think possible the clutch release and
pushrod was rigged. I think that it might be why the clutch adjustment for the cover is missing.

Nahman wrote:

So two days ago my uncle and I rented a Uhaul van to
move the bike. Bit of advice, I dont highly recommend anyone
does the same. The Kz900 is one heavy bike! My uncle and I
thought" we'll just get a couple of guys to help us lift it up
into the back..." no way. Lucky for us the Uhaul place had a
broken/detached ramp from one of there big moving trucks and
they let us use it. Even the it was still difficult. Anyhow I
have the bike home now.

Just bit of advise:

It should only take (3) people to lift a bike, (2) to lift and
(1) to hold the bike once you have the bike on the truck/van.
Also make or purchase a ramp, I can move my bike myself (for the
times when you can't find anyone around). load up the bike by a curbside,
to where the tailgate is closest to the ground. My folk's driveway leads up to their garage,
where you can just walk the bike on using a ramp.
Some old school cats taught me the last one.

I think maybe his ball bearing has powdered. Look where the pushrod has spun material on it. Can't say I have ever seen that before but it certainly looks like it has been spinning pretty damn good. Might be a complication of a few things. Ball bearing failure and mounting bolts missing.

My .02 cents

Clutch pushrod looks corroded and probably frozen. When he grabbed the clutch lever the pushrod wouldn't budge so the worm gear device that pushes the pushrod just pushed out and snapped the outer cover assembly because of the 2 missing bolts.I'm guessing that the junk on the end of the pushrod is from wear on the worm gear assembly twisting on the pushrod that isn't moving.

The fix :

1. Pull pushrod out and either replace or wire brush to get corrosion off - then relube

2. Replace outer sprocket cover assemble (the one that cracked) - used ones are pretty cheap - or better yet just buy a replacement plate from Kosman, PMFR, APE,etc. which is the way I would go.

3. Pull clutch cover, clutch spring plate, springs, clutch pusher, ball bearing behind pusher.

4. Inspect clutch pusher and ball bearing and insert new (or polished) push rod to make sure it slides easily thru from one side to the other.

5. Replace clutch pusher (or polish, wire brush) or replace with after market needle bearing pusher assembly. Replace ball bearing if necessary.

6. Lube everything back up and make sure pushrod, clutch pusher and ball bearing all move freely.

7. Reassemble

Anyway - just some thoughts

Zippy

Z1E has these parts for consideration:

mushroom

pushrod

Good Luck!

As was mentined before the te rod,pusher ,ball adjust screw welded itself together. The adjustment screw then turns itself in putting the beaking pressure on the cover. Extremely common with the old motors.