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Porting and milling options for GPZ750? 16 Dec 2014 16:47 #656217

  • kawi810
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quick story i wanted to remove my valve guides so i heated the oven to 500 degrees f let the head stay in to long and my valve seats fell out . wasted head .so becarefull when heating your head.live and learn
original owner of a 1984 gpz 750
1985 turbo 750 stock, being restored.
1984 gpz 750 with 810 cc wiesco's megacycle cams(471-10) 34 mm flatslides v&h pipe ported head dyna ignition. bottom end, crank case from turbo 750 and sprockets.

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Porting and milling options for GPZ750? 16 Dec 2014 17:55 #656226

  • SWest
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In any manual it says to measure valve to piston clearance when installing high comp. pistons and or radical cams. That piston is coming up as the exhaust valve is closing. The clearance is crazy tight. One problem and the valves are gone. Not much wiggle room there.
Steve

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Porting and milling options for GPZ750? 16 Dec 2014 18:46 #656235

  • Nebr_Rex
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It is the intake valve opening as the piston approaches t.d.c..
2002 ZRX1200R
81 GPz1100
79 KZ1000st daily ride
79 KZ1000mk2 prodject
78 KZ650sr
78 KZ650b
81 KZ750e
80 KZ750ltd
77 KZ400/440 cafe project
76 KZ400/440 Fuel Injected

www.dotheton.com/forum/index.php?topic=39120.0


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Porting and milling options for GPZ750? 16 Dec 2014 18:54 #656237

  • kawi810
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are we on topic?
original owner of a 1984 gpz 750
1985 turbo 750 stock, being restored.
1984 gpz 750 with 810 cc wiesco's megacycle cams(471-10) 34 mm flatslides v&h pipe ported head dyna ignition. bottom end, crank case from turbo 750 and sprockets.

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Porting and milling options for GPZ750? 16 Dec 2014 20:01 #656243

  • zukdave
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Kawi810 you were asking about what is the best KZ750
that would be the 83-84 ZX750A1-A2 head.
1980 KZ650 F1
ZX750A1 motor.
Wiseco 810cc kit.
Zukiworks racing ported head.
VM 29 smooth bore's.
Dyna 2000 Ign. w/Dyna mini coil's
APE cylinder stud's and nut's.
APE valve spring's.
APE Track King clutch.
V/H KZ1000 sidewinder.
3.5x18 laced to a KZ1000 disk hub.
150/60/18 Shinko 006 Podium.
63" wheel base.

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Last edit: by zukdave.

Porting and milling options for GPZ750? 17 Dec 2014 02:36 #656254

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thanks .thats the one that i have in the pics.just thought there might be something better.
original owner of a 1984 gpz 750
1985 turbo 750 stock, being restored.
1984 gpz 750 with 810 cc wiesco's megacycle cams(471-10) 34 mm flatslides v&h pipe ported head dyna ignition. bottom end, crank case from turbo 750 and sprockets.

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Porting and milling options for GPZ750? 17 Dec 2014 02:51 #656256

  • kawi810
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hey zukdave,how is your drag bike coming out ?mine will be used for drag racing only.since we are running the same engine keep me posted. john
original owner of a 1984 gpz 750
1985 turbo 750 stock, being restored.
1984 gpz 750 with 810 cc wiesco's megacycle cams(471-10) 34 mm flatslides v&h pipe ported head dyna ignition. bottom end, crank case from turbo 750 and sprockets.

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Porting and milling options for GPZ750? 17 Dec 2014 06:04 #656263

  • SWest
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Nebr_Rex wrote: It is the intake valve opening as the piston approaches t.d.c..


You measure all of them.

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Porting and milling options for GPZ750? 19 Dec 2014 11:16 #656426

  • Tyrell Corp
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Not sure about this need for high octane fuel needed for ANY CR increase. All kawis are suitable for unleaded petrol, the 550's were all 10:1 CR standard.

Interesting tuning info here, note the thinner zephyr 750 head gasket and 0.5mm head skim recommendation. Really need to know what the clearances are here - the wisecos have deeper valve pockets generally.

members.tripod.com/gpz_rider/technical/FAQ2000.htm

Note from megacycle catalouge: GPZ 750 engines made 1983 and 1984 require special 1.070" base circle diameter in some models.
All other 750 and all KZ-650 engines have a stock base circle of 1.110". To be sure, measure your stock cams





...I know 'best' isn't always biggest numbers, the older GPZ550 have slide carbs and smaller inlet tracts and whilst the later CV carb variants have more peak rpm power they don't have the same bottom and end grunt. Whether more peak power for less bottom end is an improvement will depend on riding style and conditions.
1980 Gpz550 D1, 1981 GPz550 D1. 1982 GPz750R1. 1983 z1000R R2. all four aces

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Porting and milling options for GPZ750? 20 Dec 2014 09:08 #656515

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Tyrell Corp wrote: Interesting tuning info here, note the thinner zephyr 750 head gasket and 0.5mm head skim recommendation.
members.tripod.com/gpz_rider/technical/FAQ2000.htm


Mill off .020" and you will hit the valve seats on a regular KZ750E head. Does the GPZ head have more spacing between the seats and the deck surface?

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Porting and milling options for GPZ750? 21 Dec 2014 10:12 #656615

  • Nebr_Rex
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Nessism wrote:

Tyrell Corp wrote: Interesting tuning info here, note the thinner zephyr 750 head gasket and 0.5mm head skim recommendation.
members.tripod.com/gpz_rider/technical/FAQ2000.htm


Mill off .020" and you will hit the valve seats on a regular KZ750E head. Does the GPZ head have more spacing between the seats and the deck surface?



First two pics are of a LTD(H), same as an E, silver paint instead of black.
Second two pics are of a Spectre, same as a GPz, again just paint being the difference.












.
2002 ZRX1200R
81 GPz1100
79 KZ1000st daily ride
79 KZ1000mk2 prodject
78 KZ650sr
78 KZ650b
81 KZ750e
80 KZ750ltd
77 KZ400/440 cafe project
76 KZ400/440 Fuel Injected

www.dotheton.com/forum/index.php?topic=39120.0


.
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Last edit: by Nebr_Rex.

Porting and milling options for GPZ750? 15 Jan 2015 02:29 #658743

  • Tyrell Corp
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Nessism wrote:

Tyrell Corp wrote: Interesting tuning info here, note the thinner zephyr 750 head gasket and 0.5mm head skim recommendation.
members.tripod.com/gpz_rider/technical/FAQ2000.htm


Mill off .020" and you will hit the valve seats on a regular KZ750E head. Does the GPZ head have more spacing between the seats and the deck surface?


Do you have a head you can measure:

kzrider.com/forum/2-engine/596833-cylinder-head-skim-markers

would be reallly interested thanks
1980 Gpz550 D1, 1981 GPz550 D1. 1982 GPz750R1. 1983 z1000R R2. all four aces

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