TOPIC:

Dave,
Will do some legwork on the shops and parts. I just sent Redline an email to see what is up. Will call up APE sometime within the next day or so and get a feel of how/if they can help. Maybe I'll send Joe an email just to touch base. I had emailed him on and off throughout the last few years to show him pictures of the bike when it was done. Last I had seen the PitStop website was hacked or something weird was going on with that.

I have been a forum member for quite some time and have ridden and wrenched on this bike for over 10 years; I appreciate the feedback and info.

You got me curious and I went on Redlines site just now
He has taken down his out of business message and had just updated it on 3-27-2018

And He is back from every indication Good News

Glad to see another KZ vendor available to our membership

Dave

Cracks in plug holes are very common when a Z has overheated, although it does appear that some of the thread has burnt out as well. I know you stated the the nuts for the head were not loose, can you check if the nuts were not bottomed out on the thread i.e they can be tight but a wrong washer etc causes a gap making you "think" it has been tightened.

Street Fighter LTD wrote: You got me curious and I went on Redlines site just now
He has taken down his out of business message and had just updated it on 3-27-2018

And He is back from every indication Good News

Glad to see another KZ vendor available to our membership

Dave

I have found Redline has very good parts equal to if not superior to OEM in some instances. Jim had me worried here for awhile. Redline is worth looking at for most parts and gaskets for your vintage motorcycle. We are really pretty lucky to have a number of good venders to choose from.

So many visual signs of extreme heat looking at your pictures.
Thoughts ;
Extreme air temps , poor fuel quality, low oil level, and what kind of oil was used .. what compression ratio are those pistons ?
Road conditions ; beyond air temps , elevation changes effect jetting , Lots of high speed long uphill pulls ?
air leaks in intake track ? What cams, timing, valve adjustments for lash. Where valves hanging open once warmed up ?
In other words you have some things to consider that caused your motor to burn down
Dave

Bozo,
That plug hole was actually repaired years ago with weld. The previous (original) owner had installed a helicoil many years ago. When Joe did my head, he had the damaged hole/helicoil drilled out and welded and tapped. What we see here on plug #3 is a little carnage from what is probably the repair...and then overheating related crack perhaps? (***I want to add as a side note, we took a leap of faith with the welding repair. It held up until this happened. Joe and I both thought my head was usable and this plug hole could be repaired and that worked. I am in no way blaming this repair for the current damage...just stating that a few years ago, I thought I was going to have to get a new head anyway because the helicoil was so messed up. So in a way I just postponed destiny here***)

I don't really think I can reliably check to see if the nuts were bottomed out, but this is also certainly a possibility. Each one had the copper crush washer thing which were replaced during the original rebuild.

Dave,
Temp was 90 degrees. I run an oil cooler. I don't recall the oil type or weight but it was probably Castrol 10w-40. It definitely smelled burned after draining!
Compression on the MTC kit installed was 10.5:1. Stock cams. Ignition is dyna-S and was timed appropriately according to instructions. Been running it for at least 10k miles.

When the original running-with-loose-head incident happened I checked the timing, valve adjustment, etc. I have all of this written down at home but everything was in spec 1,500 miles before the grenade happened. I do not know if the valves were hanging open...certainly a possibility. I do not think there were air leaks. Cylinders were all in sync and bike was running smoothly.

In honest opinion, (ignore the obvious carnage) do the valve surfaces / combustion chamber top / piston domes look like they were running hot or burned?

I truly think the original running-with-loose-head incident is what caused this, just got a lucky 2 thousand more miles out of it.

Have been emailing with Jim from Redline. He concurs I need to source a head and jugs.

Thanks for input everyone.

Didn't realize Pitstop did the engine. That very well may be the root of your problem. They trashed mine in every aspect.

Good thought above to be sure the nuts didn't bottom out on the studs, or the dowels bottomed out due to too much off either deck.

And I agree the crack at the plug usually comes from overheat, but I've also seen it happen removing a seized plug with too much force. Going by the builder. It may have been assembled with the crack.

Stock cylinder head studs or heavy duty?
Steve

A lot of current blends of Castrol 10-40 oil are not made for KZ ( wet clutch ) motors. So maybe take a look at which blend you were using .
OH ,
And as bad as your burned down cylinder head may look to you.

You are still a amateur in my book LMAO

A old head I keep around to remind me of the good old days

WOW, WTF HAPPENED THERE?
Steve

SWest wrote: WOW, WTF HAPPENED THERE?
Steve

To much Boost and way to much Nitrous

This head came off my teams funny bike back in the day. I had posted it years ago on KZR

when a novice member wanted to go over board with a project and I shared with the group that to much is good , but very expensive

Dave

Dave,
WOW, bet that was a surprise for the rider when that happened! Holy cow!

Steve,
Stock cylinder studs. For this reason I never torqued them past spec even though I always felt they could go a bit tighter with a 2 ft torque wrench. Did not want to break one.

VTEC,
I got a fair amount of trouble free miles after the PSP work; I had read your woes in the past and that is really unfortunate however in this case I stand by Joe's work and I am taking blame for this. Everything he did was clean and I think my work was done either before or after recovering from his health ailments.

So far I have emailed Jim @ Redline and Larry Cavanaugh in search of a head. There seems to be a shortage. I have seen a few on ebay over the last month but they have mostly had cracks in the same spot - plug holes to valves. I can't rationalize spending big bucks on a head with a crack.

I am in agreement that regardless of where the head and block come from, it is time for a complete overhaul. I want to use my same bottom end to keep my engine number and at least I know the last 10 years worth of history on it.