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Discussion Starter · #1 · (Edited)
After some research and saving I have bought a K810 kit on ebay (today I am still waiting for the delivery, but it should get here some day).
I have the plan to obtain a additional set of barrels and get those drilled to the new pistons... In order to do this, I bought (well... bought... I cost me some wine and a gift card) Z750GT. This was a mistake... the barrels on the 1992 GT are different (the cam chain tensioner is of the square type, I have a round version on my Zr7). So this plan is now being shelved, the GT (not in any thing close to running condition) will be broken and sold/given away for parts. (things like seat, drive shaft and wheel) might be interesting for people).

This basically means that I am still looking for a barrel (738CC, round cam chain tensioner system).

Are there here people that know more about this GT-series bike? Would it be interesting to use it's camshafts or perhaps the complete head?

I'll use this thread to keep you people informed and as a reference location for other K810 advernturers.
What i bought:
Wiseco Big Bore 810cc Piston Kit K810 GPZ750 KZ750 ZN750 ZN GPZ KZ 750 Dragbike | eBay

This particular seller also included in this deal 8 valve stem seals. (20 bucks).

WISECO HIGH PERFORMANCE 810cc FORGED PISTON KIT FOR KAWASAKI GPZ750 STREET APPLICATIONS
WISECO PART NUMBER: K810
TO FIT:
1980 - 1985 Kawasaki GPZ750
1980 - 1985 Kawasaki KZ750
1980 - 1985 Kawasaki ZN750 LTD
and also... the ZR7 :)
INCLUDES:
4x WISECO 4186M06900 10.25:1 COMPRESSION FORGED PISTONS
4x WISECO 2717XC PISTON RING SETS
4x WISECO S526 WRIST PINS
4x WISECO CW15 ROUND WIRE WRIST PIN LOCKS / CIRCLIPS ( PAIR )
1x WISECO W3163 HEAD GASKET
SPECIFICATIONS:

Displacement: 810cc
Bore - Standard: 66.00mm
Bore - Actual: 69.00mm
Bore - Oversize: 3.000mm
Stroke: 54.14mm
Compression Ratio - Actual: 10.25:1
Notes: Cylinder boring required.

I Thought people might want to know what I have spend so far.
(all in EURO!)
piston kit (including import) 550 euro
new engine including broken crankshaft, bus also including brand new gearbox, head, exhaust, carburetors: 300
cylinder blasting: 80
cylinder bore and honing: 200
new oil pump: 135
new main bearings for crankshaft: 110
new bearings for secondary shaft (2) 30

Total so far: 1415

Costs still to come:
gaskets, o-rings, seals abt 125
set up of new engine at dyno abt. 100
 

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Discussion Starter · #2 ·
From me to you guys the following questions:
- Is my assumption correct that the GT750 barrels are in deed DIFFERENT from my ZR7 (i could make some photo's if that would help).
- Any one out there that would be interested in Z750GT parts?
 

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Discussion Starter · #4 ·
no. just that the whole process would be much easier with a ready made set. So make 1 set Wiseco ready, (keep riding the old bike), take a friday and weekend and swap.
 

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there must be enough breakers of bikes there that you can get a barrel off a ZR7, seen a few for sale here in the uk
 

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I'd be worried about the bore vs. stroke- as in the larger bore will get more power but won't do much for the torque.
 

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Discussion Starter · #7 ·
@Custer: could you explain that a bit more? I am not sure I understand what it is you are getting at?
@shakennstirred: Probably will do that.
 

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Discussion Starter · #9 ·
My question on the barrels of the GT is now basically obsolete, the GT as well as KZ650, 750LTD and some other 4 cylinder Z-series engines, all use the SQUARE cam chain tensioner. As fare as I can tell, the Zr series is/seems the first with the round tensioner. I am not willing to take that risk and find out that the barrels have more differences and end up with an bored set that will not fit. So unless some one has done this (documented) before, I'm gonna abandon the "use a Z-series barrelset" and either have the current ones drilled, or obtain a set from a proper Zr-series bike.
 

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Just pick up some used cylinders off eBay. Save your self some headache
 

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if this works you will roast the tire of your zr7. try a extra mechanical cam chain tensioner also.
 

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bear in mind the pistons are forged in the 810 kit and will be hard on the cylinders while warming up the bike.
 

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bear in mind the pistons are forged in the 810 kit and will be hard on the cylinders while warming up the bike.
Pistons should never come in contact with the barrels as they are surrounded by the rings. It should not be a problem

Also a just to 810 is only and 18cc increase in size per cylinder, or 3mm overbore. It isn't too much. I think there is a larger kit too, but then the structural integrity of the barrels could be compromised with high stress use.
 

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Discussion Starter · #15 ·
The K810 kit has been done on the "older" "750" engines (KZ750 in the 80's and 90"s). we use basically the same engine.
and on this particular forum there are a few people that done it to a ZR7. (keifmaster?)
 

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Discussion Starter · #19 ·
Kit was delivered... I was not home... hope to pick it up somewhere this week at a local drop off point :)
 
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