OMR: '76 KZ900 Restoration/Modification

Jeff.Saunders wrote: The scrap metal on the intake side - that may make sense. Once the piston performed its vanishing trick, there's no downward motion of that piston to draw air in - so when the valve opens you have slightly positive crank case pressure that's going to exit the easiest way it can.

I'm curious about what you find when you do tear down fully - I still can't understand how the darned piston just disappeared without the valves being trashed....

happened to a friend, KLR 600, very little oil to cylinder, fried it, head was fine

OMR Did you get a chance to drop your oil pan yet?

Sorry all, been busy with other shit then KZ....

Ok, got the engine out and opened... DOH!!!! :pinch: :whistle:
KZ1000 Head off to Larry for his magic....

In trying to figure this out, best guesstimate at this time is pre-detonations!
Another thing I found, piston C-clips missing off other pistons.
Basically found 1 clip only on the other 3 pistons where they had come out. :blink: :S

Here's the basics of the wiring harness I will be fabbing up....
Subject to change on the left hand control for turn signal and horn but close enough to get started.

NOTE: Note sure if I will be going with the Oil pressure gauge as depicted...

Whoa... Double posted... AH well- Oops! :laugh:

Anyhoot, that's the game plan...
I have the original 1015 KZ1000 pistons all cleaned and measured, all good. Due to extensive heat and $$$ funds right now, set of 4 new rings/seals/gaskets and should be up and running after the first of the year.

Bottom end tranny, gearing, clutch etc... all good other then the crank so New welded crank (off a 903cc Thanks Plumi!!! ) Seals, O-rings, gaskets and APE Main bearing kit etc...

I'll post more images later....

OMR

OMR, you only had 1 wrist pin clip still in place?
When assembled was the Gap of the clip set to face with the gap of the clip, in line with the Rod? If they are set at a 90 degree to the rod, they can get Sprung and pop out.
Some don't like them, but if you use Teflon Buttons, you will never have a clip problem. You could save the new clips from a set of new pistons for a stock motor.
Have you been using Ethanol like the majority of the rest of the USA, or do you have an Ethanol free station you can by from? Is it possible the Tank of fuel you got, was Regular Unleaded, put in the wrong underground tank at the station, or maybe a mix of Diesel/ Gas? I've seen it a couple of times now, and will destroy a motor, if Diesel is mixed with Gas/ Petrol. Depends on the ratio, but a Gas/ Petrol motor with this crap run through it will rattle its self to Death, overheat, and run like crap.
Looks like you might hold the record for running a 4 cyl KZ motor on 3!!!

"you only had 1 wrist pin clip still in place?"
On 2 of 3, missing clips (1 each).
The last clip was out of the piston groove but still in the wrist pin hole.
Possibly the other 2 popped completely off during removal of the cylinder ... Same time, they weren't in the groove! :pinch:

When assembled was the Gap of the clip set to face with the gap of the clip, in line with the Rod? If they are set at a 90 degree to the rod, they can get Sprung and pop out.

Following the instructions, clip was to be 180 out from clip cut out in piston lip.


Some don't like them, but if you use Teflon Buttons, you will never have a clip problem. You could save the new clips from a set of new pistons for a stock motor....

Yup! Where are you guys obtaining these from?

Ethanol..... Depends on the ratio, but a Gas/ Petrol motor with this crap run through it will rattle its self to Death, overheat, and run like crap.

Larry and I have discussed this possibility in length and based on pre-detonation evidence in the remaining 3 pistons, very possible this is exactly what occurred....

Another reason I'm liking the idea of 8.7:1 OEM 1015cc pistons... I may loose a tad over 3% BHP so not a real big deal to me at this point in time.... The big bore will just have to wait... So get the lower end all tightened up for if & when I make that decision so I won't have to open her up again.

OMR

Check for Teflon Buttons for the KZ here: www.pingelonline.com/wrist_pin_buttons.htm
No more clip issues for sure.
Were those clips the Round Wire type, or the Square Snap-ring type with the Cir-clip pliers holes?
Gap up or down on these probably doesn't matter. But 90 to the rod can be trouble, especially under stress such as Detonation. Lot of shock load to go into each and every component.
Just curios, what heat range plugs were you running? 8's? 9's?
Have you drained the tank into a clear container and try to see if the fuel is/ was the problem?

what signs of damage was seen on the other pistons? do u see any silver specks on the spark plugs insulators ?

Thanks for the link motor...
Round C-Clips, Wiseco part #....

Just curios, what heat range plugs were you running? 8's? 9's?
BS8E's... Brand spanking new out of the box the day before tune up... She ran strong up the hill to Payson AZ ~ 100 miles then 70 miles down the hill.... :blush: :laugh:
The last 30 miles on AAA truck... :pinch:

Have you drained the tank into a clear container and try to see if the fuel is/ was the problem?
Larry and I spoke of this... Other then having it tested not much I can tell from the gas...
Here in AZ, they use the ethanol this time of year...

Prior to coming back down the hill, topped off in Payson, very possible the last fill was improper mix no doubt.... How to prove it... Ah hell who knows...

Life goes on...

Hey Marky...

"do u see any silver specks on the spark plugs insulators"...
Plugs were brand new as well... BS8E's...

Very little on the insulators but on the other 3 piston domes, on the carbon build a slight grayish/silver crystallized misting... YUP!

8's always look good to your eye in that motor in the past? With the compression etc, I think 9's might be the go, not like your going to sit around Idling or putting around with a build like that.
The fuel thing would be very hard to prove, unless other vehicles were effected. We had 26 Cars in one morning towed in from this. That was only one Shop. There were many others at different shops. All because the Truck driver had a Brain Fart.