How big can 750-4 go?

undiablo
Offline
User
Posts: 436
Thanks: 64

Re: How big can 750-4 go?

29 Aug 2018 05:11

#789954

zukdave wrote:
And yes you can see the liners between some of the fins

That is what I was talking about... However I don´t know if that is a problem.

Kawasaki KZ 750/4 LTD 1981
Kawasaki KLR 650 2011
Argentina - Buenos Aires

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

daveyg
Topic Author
Offline
User
Posts: 33
Thanks: 0

Re: How big can 750-4 go?

29 Aug 2018 14:48

#789979

Only problem I could see with that would be that iron doesn’t dissipate heat as well as aluminum does... but they make plenty of engines with just iron cylinders, fins and all are iron, look at any old HD or BSA or Triumph, all used solid cast iron cylinders before about 1970. HD took until almost the 90s to start using sleeved aluminum.

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

KZB2 650
Offline
User
Posts: 1475
Thanks: 265

Re: How big can 750-4 go?

30 Aug 2018 12:39 - 30 Aug 2018 12:40

#790009

Hey Daveyg search for Worlds biggest KZ650...... It was one of my 1st posts way back in 06. Search google and here for big bore kits for the KZ650 too and you'll pick up more info. If I had it to do over again I'd stick with the 810 Weisco kit (proven to be a strong running and tough set up ) or maybe the 831 MTC pistons if you can still find em. Have a 1980 750 block and still might someday but am running outta years fast.

1978 KZ650 b-2
700cc Wiseco kit 10 to 1.
1980 KZ750 cam, ape springs, stock clutch/ Barnett springs.
Vance and Hines Header w/ comp baffle and Ape pods, Dyna S and green coils, copper wires.
29MM smooth bores W/ 17.5 pilots, 0-6s and 117.5 main
16/42 gearing X ring chain and alum rear JT sprocket.

Last edit: 30 Aug 2018 12:40 by KZB2 650.

The following user(s) said Thank You: Nessism, daveyg

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

daveyg
Topic Author
Offline
User
Posts: 33
Thanks: 0

Re: How big can 750-4 go?

30 Aug 2018 16:53

#790019

Thanks for that info! I already found your old thread. I’m not really looking for manners or longevity really haha. Just wanna say I did it. I’m probably gonna run a pair of 40mm mikuni round slide carbs, one feeding cyl 1&2 and the second feeding 3&4, exiting out of a set of headers and a straight pipe off of each header.

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

daveyg
Topic Author
Offline
User
Posts: 33
Thanks: 0

Re: How big can 750-4 go?

31 Aug 2018 15:55

#790068

Well the original factory liners pressed out SUPER easy. Now to wait for my other (74mm) liners...

Attachments:

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

daveyg
Topic Author
Offline
User
Posts: 33
Thanks: 0

Re: How big can 750-4 go?

31 Aug 2018 16:09

#790070

Now for some math. From the fin to the casting I get approx 28mm, from the fin to the ‘bore edge’ of the existing bore (with liner removed) is approx 35.5mm, meaning I have roughly 7.5mm wall thickness before the liners would be directly exposed to the air in between the fins. Which is a radial dimension meaning there’s roughly 15mm diametrically. Should have plenty of room for the bigger sleeves I think.

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

Big Jay
Offline
Banned
Posts: 48
Thanks: 18

Re: How big can 750-4 go?

01 Sep 2018 23:54

#790131

If you make the pistons, how will you turn the cam in the skirts?

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

daveyg
Topic Author
Offline
User
Posts: 33
Thanks: 0

Re: How big can 750-4 go?

02 Sep 2018 05:38

#790134

I’ve got a lathe and a milling machine. Not sure what cam in the skirt you’re referring to though.

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

SWest
Offline
Sustaining Member
10 22 2014
Posts: 23329
Thanks: 2873

Re: How big can 750-4 go?

02 Sep 2018 05:59 - 02 Sep 2018 06:00

#790135

Miller bored out his Honda/Davidson CB 750 to 1015' The barrels were so thin he had to have them built up so they wouldn't weep. That Chopper thing would walk from my Z1b1000 until I got some cams, then it was rider against rider.
Question is how much do you want to spend when you can always get a bigger bike? :whistle:
Steve

Z1b1000 1975 Z1b
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229

Last edit: 02 Sep 2018 06:00 by SWest.

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

TexasKZ
Offline
Platinum Member
Posts: 7828
Thanks: 2421

Re: How big can 750-4 go?

02 Sep 2018 06:08 - 02 Sep 2018 06:19

#790136

Here is a brief explanation of modern skirt design including skirt cam. The skirt area is not perfectly round, is not the same diameter from top to bottom, and varies in thickness. The skirt is crucial to piston performance, and is a fairly complex bit to design and manufacture. I bet even that old Indian would have gone faster with a carefully designed and manufactured set of pistons.

blog.jepistons.com/maximizing-horsepower...piston-skirt-shaping

1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough

www.kzrider.com/11-projects/620336-anoth...uild-thread?start=24

Last edit: 02 Sep 2018 06:19 by TexasKZ.

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

650ed
Offline
User
Posts: 15343
Thanks: 2830

Re: How big can 750-4 go?

02 Sep 2018 06:22

#790138

SWest wrote: ..................Question is how much do you want to spend when you can always get a bigger bike? :whistle:
Steve

Excellent question! For example, given enough funds one could use (make) a 750 turbo engine and with appropriate mods turn it into a monster such as one in the link below. Ed

www.750turbo.com/forum/viewtopic.php?f=9...f51c1956060ca2366de2

1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)

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

Nessism
Away
Sustaining Member
Posts: 7660
Thanks: 3031

Re: How big can 750-4 go?

02 Sep 2018 10:21 - 02 Sep 2018 19:19

#790153

daveyg wrote: Not sure what cam in the skirt you’re referring to though.

Pistons are not round.

Ed
Carb O-ring Kits : www.kzrider.com/forum/3-carburetor/61807...-o-ring-kits?start=0

www.kzrider.com/forum/faq-wiki/618026-new-owner-things-to-know

1981 KZ750E2
www.kzrider.com/forum/11-projects/604901...z750e-project-thread

Last edit: 02 Sep 2018 19:19 by Nessism.

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