Top-End Reassembly

Been a while since I felt a need to do this:


Ten years, actually...



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After hours hand-scraping material from the piston pocket edge, to gain sufficient clearance for the intake valves...which are stock btw.

Looks like I have more to do, and $pend...





But how is this clearance work necessary if the K1172 piston kit is designed specifically for this 84 ZN1100B motor?

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The MTC G1135-3 kit was installed in my old motor with the same head and cam setup, that I ran for six years with no issues.

Note the differing valve pocket locations shown below. 






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That's a very interesting find Daveo? Did a little research thru Wiseco and apparently, they offer two different versions for the ZX11. A 10.25cr which your stamping denotes and a 4380M7500 9.5cr. Maybe because you're using the bathtub head the crown of the piston would be constructed higher to compensate? I have seen because i have experienced it thru a shop that didn't know the difference. The Wiseco set box stated incorrect info on the box, last photo shows blatant incorrect info. You have the newest pistons because of the machinist ink instead of the pin-pricked font. Your pistons look more like 11 to 12.5cr then what i'm used to similar? Are they Genuine Wiseco, never know these days, ha.         

Based on these piston-clay impressions, what additional valve clearance needs to be provided?






This impression appears to show the exhaust valve barely clears the piston top at the pocket edge...

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Goofy comment deleted.

TexasKZ wrote:

Goofy comment deleted.
 

No problem, the more the merrier!

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A couple things if it helps? The initial photos showed where the margin of valves were pushing down liner side material of piston valve pocket. Do You remember an incident indexing cams back during installation? You very well could of bent those valves albeit slight but would definitely create a loss of efficacy. I know it shouldn't make a difference but i see you are using an MLS head gasket, might have a thinner stacked height? If You had the cylinder and head surfaced, did you have too much removed and didn't compensate for it, usually a thicker base gasket or double stack those .020" per. Don't know but things to consider.     

asphalt900 wrote:

A couple things if it helps? The initial photos showed where the margin of valves were pushing down liner side material of piston valve pocket. Do You remember an incident indexing cams back during installation?
 

No sir.  No mis-indexes or mistaken chain pin counts.  The sprocket arrows consistently aligned with the head surface.

I believe the valve lip was catching the pocket wall as the piston was pulling away, rather than jamming into it as the piston was rising...more like scraping together, if that makes sense.

Chris Schumann has the cylinder head.  He is making new valves to replace the original factory set.  Said the intake valves were ok, but the piston/valve rubbing action had worn the guides out of spec at full open position.
Had there been valve impact with the piston while coming toward each other, this fiasco wouldn't be happening, and my riding season would have ended before it started.

As the cylinder head from this 1984 ZN1100-B1 LTD engine is out for repair...

I decided to clean up my other 84 ZN1100 head, and use it for the Wiseco K1172 piston clay mockup.

Images below include comparative measurements with an original 84 Kawasaki ZN/ZX1100 13001-5011 piston removed from this motor.





Comparative measurements:
Note the Wiseco measurement was 62mm +/- BEFORE the pocket was modified for the intake valve to clear.





And the following:








Gap measurements:





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For these K1172 pistons to work in this motor, the intake valve pocket MUST be modified for clearance.

Since the ehaust valve travel stops short of touching the piston, why is such an enormous pocket necessary?  

But for the potential use of bigger cams (and/or larger valves) in the future, the exhaust pocket will be extended toward the piston edge.





Wiseco disclaims any responsibility for this co$tly fia$co, so I am on my own moving forward...

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1984 ZN1100B LTD/ZX1100A Bathtub Head valve angle check:



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seems bizarre !! where the pistons intended for use with a bathtub head ? (never heard of Wiseco getting it this far wrong !!)

Tell him what you told me dave.