Kz750 VM28ss

  • Maxbou92
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Kz750 VM28ss

02 Jan 2024 07:19
#893430
Hello everyone, my project is now done. Ready for this summer. I would like to know what jet I should put in my VM28ss from Z1r in my KZ750 . Now I have 107.5 main and 15 pilot(vm28ss carb). Carburetor are freshly rebuilt, adjusted on point!! My Motor has a 0.5mm oversize, small porting, milled 0.006’’, pod filters, exhaust 4-1 w/o baffle !! Im located to Canada, quebec. My altidude is 400 meter..  I see some of you start with 117.5 main and 17 pilot, but I don’t know the altitude for these set up… ?!! 
Thank you so mich
Kz750e 1980

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  • Nessism
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Re: Kz750 VM28ss

02 Jan 2024 11:06
#893438
You might want to contact member Zed, for some air correction jets.  That will make a huge improvement.   Also, make sure your pods are real deal K&N, or similar.  Cheap china pods sometimes lead to tuning problems.

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  • Mikaw
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Re: Kz750 VM28ss

02 Jan 2024 12:50
#893441
Just to confirm the carbs in the included photo are not VM carbs. They are BS, vacuum slides. Completely different. Are you identifying your carb rack correctly?
1976 KZ 900 A4 kzrider.com/forum/11-projects/613548-1976-kz-900-a4
1976 KZ 900 B1 LTD
1978 KZ 1000 B2 LTD
1980 KZ 750 E1
Kowledge Speaks, But Wisdom Listens.
Jimi Hendrix.
The following user(s) said Thank You: sf4t7

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Re: Kz750 VM28ss

02 Jan 2024 13:13
#893443
Ok I will try to find these air corrector jet on ebay.. and what size of these one a need to put first ?! And Yes for the picture it was last year with The CV34mm !!
Kz750e 1980

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Re: Kz750 VM28ss

02 Jan 2024 13:16
#893444
Ok I will try to find these air corrector jet on ebay.. and what size of these one a need to put first ?! And Yes for the picture it was last year with The CV34mm !!
www.kzrider.com/forum/forum-index/23-for...-round-slide-mikunis

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  • Mikaw
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Re: Kz750 VM28ss

02 Jan 2024 18:47
#893462
Ok I will try to find these air corrector jet on ebay.. and what size of these one a need to put first ?! And Yes for the picture it was last year with The CV34mm !!
Post a current picture I’m sure the group would like to see the transformation. 
1976 KZ 900 A4 kzrider.com/forum/11-projects/613548-1976-kz-900-a4
1976 KZ 900 B1 LTD
1978 KZ 1000 B2 LTD
1980 KZ 750 E1
Kowledge Speaks, But Wisdom Listens.
Jimi Hendrix.

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  • Maxbou92
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Re: Kz750 VM28ss

03 Jan 2024 11:15
#893512
Thank you, do you think that the bike will be more powerful with these carbs and run better? The CV one was very hard to tune and I was not happy at all to ride it.. 
Kz750e 1980

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  • Injected
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Re: Kz750 VM28ss

04 Jan 2024 09:24 - 04 Jan 2024 09:25
#893557
Thank you, do you think that the bike will be more powerful with these carbs and run better? The CV one was very hard to tune and I was not happy at all to ride it.. 

 
Switching from the CV34's to VM28's will probably not give you a performance increase. I guess it depends on how badly it was running with those CV carbs.

VM28's are not a "performance" carb like a smooth bore or a flat slide which do have a "bolt on" HP increase associated.

Most times poor performance may be due to other engine issues (no valve clearance, low compression, etc) but owners always assume it to be a carb issue.

A 110 main and a 15/17.5 pilot sounds about right for pods/pipe on a 750, but 117.5 is way too big for a stock 750.

There are jetting recommendations for altitude but generally that only applies if you go past 1000 feet (300M) in elevation gain so you could stick to a stock setting.
1978 KZ650B2 w 1197cc Z1 engine
1977 KZ650B1 w 750cc Spectre engine
1979 KZ650C3 w 831cc Hot Rod engine
1978 KZ650C2 w 762cc DFI project
1977 KZ650C1 stock restoration project
1978 KZ650B2 modified project
1978 KZ650B2 Injected Drag 831cc
1980 Z1 Custom Frame Drag 1327cc
1981 Z50R Honda tow bike
Last edit: 04 Jan 2024 09:25 by Injected. Reason: sp
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  • Maxbou92
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Re: Kz750 VM28ss

04 Jan 2024 13:08
#893575
My engine is brand new!! Valves are in specs and 150psi on each cylinders!! Thank you!! I have a 17.5 pilot now and 117.5 for starting
Kz750e 1980

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  • gordone
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Re: Kz750 VM28ss

18 Jan 2024 14:18
#894156
With pods the aircorrected jets was spot on for me!
1981 KZ650-D4, with 1981 z750L engine (Wiensco 810 big bore).

Project:
www.kzrider.com/forum/11-projects/607213...sr-1981-z750l-engine

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Re: Kz750 VM28ss

19 Jan 2024 03:28
#894161
Can you tell me how to install these jets and what kind I need ?! If I put on dyno, does the guys need it for a good tune ?
Kz750e 1980

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Re: Kz750 VM28ss

19 Jan 2024 06:22
#894169
Can you tell me how to install these jets and what kind I need ?

A link to the person selling the Air Correction jets was already provided to you in this thread...

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