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Gpz 750 road racing engine build 08 Oct 2021 14:09 #856383

  • richard
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Building a back up motor for my road racing bike, the dry clutch build was a success, just finishing up the head,will have pics up soonwill try to document the entire build from valve cover to oil pan as it progresses 
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Gpz 750 road racing engine build 08 Oct 2021 15:02 #856386

  • 750 R1
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Hi Richard, I'm about to have my 750/810 built so I'm in for the ride. More info about that dry clutch too please. I'm going to try and use a  TPS on the carbs, with a programmable electronic ignition, if it works,  it should be an interesting mod..   What did you do to the ports ?  What valve springs did you use and what was the seat pressure..

Thanks

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Gpz 750 road racing engine build 08 Oct 2021 17:49 #856395

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Hi there was a complete build on it last winter in this  project section
there was some intial issues that have since been corrected 
it works perfect,no slippage whatsoever,smooth shifts and the rattling messes with the other racers LoL

Did all my port work in my garagePlugged the exhaust emission holes  and the springs are ape Vs900k because I use a megacycle 410 lift cam  
  
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Gpz 750 road racing engine build 08 Oct 2021 18:20 #856399

  • Dr. Gamma
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I love your dry clutch setup. That took some real engineering and machining to come up with that setup!!!!!

Now your cylinder head porting is more than impressive. The consistency of the shape and finish of your finished ports is up there with some of the big buck heads I had ported over the years!!!! 

 
1972 H2 750 Cafe Racer built in 1974.
1976 KH400 Production Road Racer.
1979 Kz1000 MK. II Old AMA/WERA Superbike.
1986 RG500G 2 stroke terror.
1986 GSXR750RG The one with the clutch that rattles!

Up in the hills near Prescott, Az.
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Gpz 750 road racing engine build 08 Oct 2021 18:54 #856402

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Thanks it's my 3rd try, not my favorite part of doing the engine
but I'm too cheap to pay someone else LoL
It's a sick feeling when you detroy a head and all the work goes down the toilet
destroyed my first head  when we broke a tack during a race weekend and had no rev limiter,the bucket is somewhere on the track lol
Live and learn.,rev limiter is now installed 


 
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Gpz 750 road racing engine build 09 Oct 2021 06:45 #856414

  • ThatGPzGuy
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I'm on board. My GPz750 has over 30K on the clock and I have an 810 kit on the shelf so it's gonna happen. 
Jim
North GA
2016 Yamaha FJR1300ES
1982 GPz750 R1
1974 Kawasaki H1
1976 Kawasaki KZ400
1979 Yamaha XS650 cafe'
2001 KZ1000P
2001 Yamaha YZ426
1981 Honda XR200 stroked in an '89 CR125 chassis
1965 Mustang
1967 Triumph GT6
1976 Bronco
"If you didn't build it, it's not really yours"

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Gpz 750 road racing engine build 09 Oct 2021 09:59 #856422

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Took the head to work in order to grind,it's rarely done this wayBut have no access to a quality head resurfacer, I've always done it this way
no chances of tool chatter as it cuts slightly into the hard valve seats on the intake side 
.025 was taken off in order to get more squeeze out of it
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Gpz 750 road racing engine build 09 Oct 2021 15:50 #856458

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Nice work on the clutch, and those ports, I have a spare head without top cam caps, so might have to practice on that...  What compression did you end up with ?  
Have you run this engine yet ? 

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Gpz 750 road racing engine build 09 Oct 2021 17:03 #856465

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Thanks on the clutch
not sure on the compressionA brief history
first engine blew up2nd engine with dry clutch
​​​​​​is presently in the race bikeHead shown is being prepared for a back up motor

Had to make 8 guides from c954 bronze,I know they could be ordered
But I was in a rush and knew I wanted certain dimensions
Then was able to grind the seats for the valves  
 
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Gpz 750 road racing engine build 09 Oct 2021 17:13 #856467

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Valves all ground
reàdy for install
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Gpz 750 road racing engine build 10 Oct 2021 10:48 #856498

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After a few seats were cut a bit deep because of new guides had to make a few .020 shims to accommodate for the difference Then had to machine the keepers After the valve stems were ground if you don't have an expensive valve spring checker,this vice method is the next best thing 
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Gpz 750 road racing engine build 20 Oct 2021 05:07 #856830

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