Porting KZ heads
- SWest
-
Topic Author
- Offline
- Sustaining Member
- 10 22 2014
- Posts: 23346
- Thanks: 2882
Porting KZ heads
25 Mar 2020 15:17 - 25 Mar 2020 15:33
I'm starting this thread to get suggestions on porting KZ heads. Larry's FB page has lots of pics but no how to instructions. The ones on YouTube aren't KZ specific and I don't trust them. We lost a wealth of knowledge with his passing. 
The porting I did on the head I am using now seems to work well but by his pics it looks like I could have gone farther. I'm getting ready to do the original head so pics and pointers would be appreciated.
Steve
www.facebook.com/pg/cavanaughracingheads...s/?ref=page_internal

The porting I did on the head I am using now seems to work well but by his pics it looks like I could have gone farther. I'm getting ready to do the original head so pics and pointers would be appreciated.

Steve
www.facebook.com/pg/cavanaughracingheads...s/?ref=page_internal
Z1b1000 1975 Z1b
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229
Last edit: 25 Mar 2020 15:33 by SWest. Reason: sp
Please Log in or Create an account to join the conversation.
- Nessism
-
- Offline
- Sustaining Member
- Posts: 7672
- Thanks: 3045
Re: Porting KZ heads
25 Mar 2020 16:46
Steve,
You're not building a race bike there. Just smooth out the casting flaws, paying attention to the short side radius which tends to have a sharp edge, and call it done. Hogging out material without knowledge and a flow bench can do more harm than good.
You're not building a race bike there. Just smooth out the casting flaws, paying attention to the short side radius which tends to have a sharp edge, and call it done. Hogging out material without knowledge and a flow bench can do more harm than good.
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
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
The following user(s) said Thank You: SWest
Please Log in or Create an account to join the conversation.
- SWest
-
Topic Author
- Offline
- Sustaining Member
- 10 22 2014
- Posts: 23346
- Thanks: 2882
Re: Porting KZ heads
25 Mar 2020 17:04
That's pretty much what I did. I'm having to download my clips to take snapshots of the ports and seat areas. I didn't think to do them at the time I recorded them. :blush: Here's a few. More to come. I'm always open to suggestions on how to make them better. 
Steve

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
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229
Please Log in or Create an account to join the conversation.
- Street Fighter LTD
-
- Offline
- Moderator
- TURBO, Its Better to be Blown than Injected
- Posts: 4972
- Thanks: 2123
Re: Porting KZ heads
25 Mar 2020 17:41Nessism wrote: Steve,
You're not building a race bike there. Just smooth out the casting flaws, paying attention to the short side radius which tends to have a sharp edge, and call it done. Hogging out material without knowledge and a flow bench can do more harm than good.
Yeah , What ED said
Head air flow work is not for the amateur. I had a Superflow 110 flow bench in one of my spare bedrooms when I was single and it still was
a heavy learning curve for my buddy Ted. It is part experimenting , practicing , measuring , testing , and magic.
Over my pay grade other than just cleaning them up and checking for balance between all the 8 ports.
Dave
Original owner 78 1000 LTD
Mr Turbo Race Kit, MTC 1075 Turbo pistons by PitStop Performance , Falicon Ultra Lite Super Crank, APE everything. Les Holt @ PDM's Billet Goodies . Frame by Chuck Kurzawa @ Logghe Chassis . Deep sump 5qt oil pan. RIP Bill Hahn
The following user(s) said Thank You: SWest
Please Log in or Create an account to join the conversation.
- Dr. Gamma
-
- Offline
- Sustaining Member
- Posts: 1230
- Thanks: 689
Re: Porting KZ heads
25 Mar 2020 18:09 - 25 Mar 2020 18:43
I have always sent my cylinder heads to the people do them for a living. There is more to it than just making the ports shiny and smooth!!!! Start measuring a big dollar cylinder head, and you will find out that everything is the exact in all of the four ports,. All four intake ports are within a few thousands of each other. Same with the exhaust ports. CC the chambers and they are all hold the very same amount of fluid. Same with the valve seats on the four valves.
One thing I have seen about flow benches, some people take their measurements at like .400 thousands lift. You will always get great numbers at that lift. Start taking your readings at like .040 thousands and see what you get. Yea for drag racing all you want is maximum horsepower wide open!!! Now that type of power curve won't cut it for road racing or street riding. I would rather have a cylinder head set up to have a nice wide powerband over one that comes on like a light switch!!! You can get a lot better drive out of corners with a wide spread of power. Same with street riding. Either one you don't spend all your time at wide open throttle!!!!
One thing I have seen about flow benches, some people take their measurements at like .400 thousands lift. You will always get great numbers at that lift. Start taking your readings at like .040 thousands and see what you get. Yea for drag racing all you want is maximum horsepower wide open!!! Now that type of power curve won't cut it for road racing or street riding. I would rather have a cylinder head set up to have a nice wide powerband over one that comes on like a light switch!!! You can get a lot better drive out of corners with a wide spread of power. Same with street riding. Either one you don't spend all your time at wide open throttle!!!!
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.
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: 25 Mar 2020 18:43 by Dr. Gamma.
The following user(s) said Thank You: SWest, Scirocco
Please Log in or Create an account to join the conversation.
- SWest
-
Topic Author
- Offline
- Sustaining Member
- 10 22 2014
- Posts: 23346
- Thanks: 2882
Re: Porting KZ heads
25 Mar 2020 18:09
I read here Joe at Pit Stop Performance said just a light cleanup of the ports will give you more power and warned not to hog out too much. He also said it would be most noticeable at WOT.
I have a friend that's in to this kind of thing and he talked about going the other way by building up to improve velocity.
With input from some of our knowledgeable members maybe it could prevent newcomers from making the same mistakes.
Steve
I certainly wouldn't suggest doing what this guy did. :ohmy:
I started with this
I have a friend that's in to this kind of thing and he talked about going the other way by building up to improve velocity.
With input from some of our knowledgeable members maybe it could prevent newcomers from making the same mistakes.
Steve
I certainly wouldn't suggest doing what this guy did. :ohmy:
I started with this
Z1b1000 1975 Z1b
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229
Please Log in or Create an account to join the conversation.
- DFIGPZ
-
- Offline
- User
- Posts: 618
- Thanks: 121
Re: Porting KZ heads
26 Mar 2020 12:57
YEP send them to people who know what they are doing ! you can do more damage than good
1984 750 Turbo
Please Log in or Create an account to join the conversation.
- daveo
-
- Offline
- Premium Member
- Posts: 2914
- Thanks: 745
Re: Porting KZ heads
26 Mar 2020 15:59DFIGPZ wrote: YEP send them to people who know what they are doing ! you can do more damage than good
I would like a basic port job done on this head, and have the broken cooling fin properly welded with no evidence of repair.
Will reuse the stock valves, and only replace guides if necessary. Have valves and seats cleaned up, and achieve balanced flow across all four cylinders.
How much $hould I expect to lay out for that?
:whistle:
.
1982 KZ1100-A2
Please Log in or Create an account to join the conversation.
- Mr. E
-
- Offline
- User
- Posts: 65
- Thanks: 12
Re: Porting KZ heads
26 Mar 2020 16:08
I would imagine $800 for a reputable shop.
1978 kz1105 - the Rooster, 1981 KZ750 Chopper, 1975 KZ400 , 1984 GPZ750
The following user(s) said Thank You: daveo
Please Log in or Create an account to join the conversation.
- SWest
-
Topic Author
- Offline
- Sustaining Member
- 10 22 2014
- Posts: 23346
- Thanks: 2882
Re: Porting KZ heads
26 Mar 2020 16:15
Z1b1000 1975 Z1b
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229
Please Log in or Create an account to join the conversation.
- M_a_t_t
-
- Offline
- Sustaining Member
- Posts: 254
- Thanks: 41
Re: Porting KZ heads
26 Mar 2020 17:04
I think PDM fabrication said he has done head work before (forum sponsor).
83 KZ1100A (shaft)
17 Versys X 300 abs
81 kz650h1
81 kz750e2
90 Honda CBR600F (brother's)
17 Versys X 300 abs
81 kz650h1
81 kz750e2
90 Honda CBR600F (brother's)
Please Log in or Create an account to join the conversation.
- SWest
-
Topic Author
- Offline
- Sustaining Member
- 10 22 2014
- Posts: 23346
- Thanks: 2882
Re: Porting KZ heads
26 Mar 2020 18:03
A good person to ask. 
Steve

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
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229
Please Log in or Create an account to join the conversation.