Gpz 750 road racing engine build

richard
Topic Author
Offline
User

08 Oct 2021 14:09 - 08 Oct 2021 14:22 #856383 by richard

Gpz 750 road racing engine build was created by richard

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

Last edit: 08 Oct 2021 14:22 by richard.

Please Log in or Create an account to join the conversation.

750 R1
Offline
User

08 Oct 2021 15:02 #856386 by 750 R1

Replied by 750 R1 on topic Gpz 750 road racing engine build

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

Please Log in or Create an account to join the conversation.

richard
Topic Author
Offline
User

08 Oct 2021 17:49 #856395 by richard

Replied by richard on topic Gpz 750 road racing engine build

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

Please Log in or Create an account to join the conversation.

Dr. Gamma
Offline
Sustaining Member

08 Oct 2021 18:20 - 08 Oct 2021 18:23 #856399 by Dr. Gamma

Replied by Dr. Gamma on topic Gpz 750 road racing engine build

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.

Last edit: 08 Oct 2021 18:23 by Dr. Gamma.

Please Log in or Create an account to join the conversation.

richard
Topic Author
Offline
User

08 Oct 2021 18:54 #856402 by richard

Replied by richard on topic Gpz 750 road racing engine build

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

Please Log in or Create an account to join the conversation.

ThatGPzGuy
Offline
Sustaining Member
More Sparky than Speed Racer

09 Oct 2021 06:45 #856414 by ThatGPzGuy

Replied by ThatGPzGuy on topic Gpz 750 road racing engine build

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"

Please Log in or Create an account to join the conversation.

richard
Topic Author
Offline
User

09 Oct 2021 09:59 #856422 by richard

Replied by richard on topic Gpz 750 road racing engine build

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

Please Log in or Create an account to join the conversation.

750 R1
Offline
User

09 Oct 2021 15:50 - 09 Oct 2021 15:51 #856458 by 750 R1

Replied by 750 R1 on topic Gpz 750 road racing engine build

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 ?

Last edit: 09 Oct 2021 15:51 by 750 R1.

Please Log in or Create an account to join the conversation.

richard
Topic Author
Offline
User

09 Oct 2021 17:03 - 09 Oct 2021 17:08 #856465 by richard

Replied by richard on topic Gpz 750 road racing engine build

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

Last edit: 09 Oct 2021 17:08 by richard.

Please Log in or Create an account to join the conversation.

richard
Topic Author
Offline
User

09 Oct 2021 17:13 - 09 Oct 2021 17:14 #856467 by richard

Replied by richard on topic Gpz 750 road racing engine build

Valves all ground
reàdy for install

Last edit: 09 Oct 2021 17:14 by richard.

Please Log in or Create an account to join the conversation.

richard
Topic Author
Offline
User

10 Oct 2021 10:48 - 10 Oct 2021 10:59 #856498 by richard

Replied by richard on topic Gpz 750 road racing engine build

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