ooo, the Z1 motor is FUBAR'D BIG TIME NOW WITH PICS

At the end of last season- I thought I dropped a valve in my ol' Z1. I have never had the cases apart on this bike, and I have owned it since 1982ish. Maybe 1984? I think 84 maybe?

Anyway- I decided to tear it down and get started on the Z1 for spring, thinking maybe a block and head changeout- boy, was I mistaken!

I pulled off the head- the piston is GONE- I mean, as if it never existed- no metal or anything- just a wrist pin welded on to a rod, and a pretty banged up cylinder sleeve.

I will post pics tonight- but damn, first time I have ever had a piston up and dissappear!

Blessing in disguise, as I can now put all the parts I wanted to put on this thing now- including the chassis mods and the welding I wanted to do- including fabb-ing a new swing arm- which I have ordered the chrome moly, made the jig, and am machining up the axle plates this next tuesday.

So, I start welding on the frame this next week- woo hoo!

I have 2 spare motors, and unless these cases are damaged, I will commence with the polishing and powder coating- the lowers I will polish and coat clear, the heads and block, will be red with the outside of the fins having natural finish. the frame will be silver, and the rest of the bike, candy apple red. The fork lowers will be candy apple red, the hubs will be candy apple red as well- as well as the calipers.

It is a departure from the last 15 years of the bike being monochromatic red!

Post edited by: CruisingRam, at: 2008/02/09 01:38

What was happening before you thought you dropped the valve?

Can't wait for the pictures.

And for the results on the metal for the swingarm.

We were on a "spirited" ride for maybe, oh, three or more hours. couple hundred miles. Finally got the motor running really good- not too rich, not too lean, by plug reading. Little bit rich, if anything- no lean burn here!

Started to act like it was out of fuel about 40 miles from home- and it was! Filled it up- died again about 15 miles later- I restarted it- no knocking sounds, no bad noises, no hard smoking- until the last few seconds it ran- then a big puff of black smoke. Still running though- but I shut it off, rode two up back home, got the truck, came and got it. Looked in the spark plug hole, looked like a valve and dropped way down in the cyclinder- turns out I was looking at the wrist pin!

Would start and fire even when I put it on the stand- with the cylinder next to it still firing- but it turned out the pin was about to seize there too- it was very tight when I checked it last night.

Rugged bitch it is! :laugh:

So, for the first time since it was borned- it will have the cases split- I have my fingers crossed that they are still good, I want to keep the stock VIN on the motor ID pad.

when i was much younger on my 78 z1r i had a piston splode in #2 hole(after a spirited ride with my brother on his gpz550 giant killer) folded the wristpin over the end of the rod.i pulled the drain plug and started draining the oil and some chunks started falling out,followed by about 1 third of an oil control ring.apparently my intake valve was opened and my air cleaner was full of aluminum dust.the top of the cases were banged up but i can save them.it was my original cases for the z1r also.that was about 5 motors ago.when i was younger i liked to run for an hour or so at redline.hopefully you can save the cases.

Well, I will be visiting this board a bit more now, since I will need to refresh my memory on several items-

I bought a set of 1000cc high compression pistons from, um, Sandy? I think? Damn I have bought alot of stuff of the people on this board :laugh: - anyway- I am porting the head, puttin the 409 cams in it, and putting some more HP to the ground. I am in "gear back cutting" class with a Kawasaki sensai in the next week or so, along with the head porting tips he is going to do for me.

So, the Z1 is in for some TLC, and hopefully, needs to be show-worth by the 29th of March!:ohmy:

Dang, CR. That sucks big time.

Any ideas? Loss of oil pressure or was one carb a bit lean perhaps?

Kind of makes a guy wonder.

N0NB wrote:

Dang, CR. That sucks big time.

Any ideas? Loss of oil pressure or was one carb a bit lean perhaps?

Kind of makes a guy wonder.

I am going to guess contaminated oil at this time- just an educated guess + a hunch. :whistle:

here is the deal- that case hadn't been split since the day Kawasaki made her. I resurected it from storage after 15 years. I said "let's chance it, I have more motors" in regards to tearing it down and cleaning it up- and, the reason for the bike being parked was the changing of a gear, forget which one, that was lunched back in the early nineties, and I think there was still some particulate matter in there, even though it ran for two seasons, though not well until the damn end:ohmy:

So I am thinking it was a delayed death. :blush:

Well, I have this bike to thank for me getting into the bike building biz- after all, I couldn't find anyone to do anything in this town that I wanted them to do- period. No one would touch it.

So I went from "put this thing together for me, I don't want to have to screw with it" to- "I build custom bikes for a business" in about 3 years. :blink:

So- if this business turns out succesful enough to be my full time occupation- I will certainly let my son or daughter inherit it!:laugh:

Well, motor out, commencing work!

I loaned my '73 Z1-900 to a 'friend' once a long time ago. While riding my Z1 a week later my engine suddenly made a horrific metal-to-metal noise so I used the kill switch to stop the motor at speed as soon as I could and pulled over to the side of the road.

When I took the cylinder head off, the #2 intake had broken off and imbedded what was left of its valve stem behind the valve head into the top of the piston, damaging the cylinder head including the intake valve seat and depositing a large chunk of that piston in the crankcase. And while this chunk of piston was making its way down into the crankcase, it was squeezed between the spinning crankshaft and the case, denting that part of the case a little. It turned out that the other three pistons had markings where they had been touched by their respective intake valves too. Guess I needed a rev limiter back then -or better friends.

I had the damaged areas of the aluminum head in #2 welded up. I cut down the intake valve seat to remove the nick in the seat that the broken valve had made, making way for installation of a 37.5 mm intake valve. Got to make lemonaid from lemons you know.

I now have a Dyna 2000 system on my Z1 with a built-in rev limiter ... and better friends.

Funny thing is- I thought it was a valve train problem- nothing of the sort, what I thought was a valve I was looking at, was the piston pin- the heads look fine! :ohmy:

Wow CR...wholly!
The piston actually dropped?!!
Make sure You post pics of what you find when you pull the pan!:ohmy:

(and yes,it was me you got the pistons from...glad you're going to be using them,bud)