Mikuni 26mm not fitting on KZ650 head

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Mikuni 26mm not fitting on KZ650 head

21 Feb 2023 19:25
#880614
Hi there, 

I am trying to mount up my freshly rebuilt 26mm carbs off a KZ900 on my KZ650. The throttle cable guide is hitting the valve cover causing the carb boots to not fully seat. Has anyone else seen this or have any suggestions? See picture where the boot is fully seated on the carb but the top won’t come in flush to the head. 

thanks! 

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  • Scirocco
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Re: Mikuni 26mm not fitting on KZ650 head

21 Feb 2023 22:34 - 21 Feb 2023 22:38
#880617
I could be wrong but in my opinion you have to swap the Mikuni 26 carb bodys to the KZ650 mounting plate, so you can use the throttle cable bracket and idle screw adjuster.This to gives you more offset and space to the valve cover. Check the carb bore diameter in the 650 mounting plate first.

 
 
 
My 1975 Z 1 B 900 Project

www.kzrider.com/forum/11-projects/605133...ears-deep-sleep-mode
Last edit: 21 Feb 2023 22:38 by Scirocco.

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  • kevski
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Re: Mikuni 26mm not fitting on KZ650 head

21 Feb 2023 23:00
#880618
You need the carb to head boots for the 900/1000 bikes and you have to elongate the bolt holes in them.

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Re: Mikuni 26mm not fitting on KZ650 head

21 Feb 2023 23:00 - 21 Feb 2023 23:03
#880619
Unless you have increased the size with a big bore kit there is absolutely no point in increasing the carb size on a 650. Of all the z's the 650 has the biggest carbs to engine capacity ratio.
If you have tweeked the cams/compression/ports etc then jetting changes is the way to go as vm24's have more than enough capacity to supply enough air. 
Z650
Vm24 dia = 452mm sq x 4 = 1808mm sq div by 652cc = 2.77mm sq per cc.
Z900
Vm26 dia = 531mm sq x 4 = 2124mm sq div by 902cc = 2.35mm sq per cc.
Z1000
Vm26 dia = 531mm sq x 4 = 2124mm sq div by 1015 = 2.09mm sq per cc. 
 
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Z1000J2 somewhat modified!
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Last edit: 21 Feb 2023 23:03 by Warren3200gt.

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  • sflesch94
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Re: Mikuni 26mm not fitting on KZ650 head

22 Feb 2023 04:27
#880622
I have the 900 boots and have modified them to fit the 650 head mounting holes. The bike has a big bore kit that’s why I am going to 26mm. I did not think about using the 24mm mount, I will have to look into that. From what I read from others, many have put these carbs on a 650 before, but no mention of interchanging parts. 

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Re: Mikuni 26mm not fitting on KZ650 head

22 Feb 2023 06:56
#880627
The 900/1000 cam cover doesn’t have the bolt at the front and back of the cam chain tunnel as yours does. That’s where your loosing clearance. As mentioned compare the 650 rack mount to the 900. Some 28 mm from 79/80 1000 have the adjuster on the bottom, same carb flange bolt pattern, that setup my help you clear that tunnel bolt. 
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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Re: Mikuni 26mm not fitting on KZ650 head

22 Feb 2023 07:52 - 22 Feb 2023 07:53
#880631
If you don't want to mess about either modifying the cable bracket or rebuilding them onto a 650 backplate (if they fit and there's no other knock on effects of that)  then simply space the inlet rubbers away from the head with some 10mm plate.
You can then either arrange the through holes the correct width to fit the head and the threaded holes in the plate the correct width for the rubbers or just make them fit the head and bolt straight through with the slotted 900 rubbers.

These in the pic are what i made to both move the cable bracket away from fouling the camcover bolt as you need and also to respace the rubbers to accept the wider spaced Mikuni VM32's from a 1000 Katana.





AIR CORRECTOR JETS FOR VM CARBS AND ETHANOL RESISTANT VITON CHOKE PLUNGER SEAL REPLACMENT FOR ALL CLASSIC AND MODERN MOTORCYCLE CARBURETTORS
www.kzrider.com/23-for-sale/611992-air-c...lide-mikunis?start=0





Last edit: 22 Feb 2023 07:53 by zed1015.

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Re: Mikuni 26mm not fitting on KZ650 head

22 Feb 2023 08:20
#880632
zed1015 wrote:
If you don't want to mess about either modifying the cable bracket or rebuilding them onto a 650 backplate (if they fit and there's no other knock on effects of that)  then simply space the inlet rubbers away from the head with some 10mm plate.
You can then either arrange the through holes the correct width to fit the head and the threaded holes in the plate the correct width for the rubbers or just make them fit the head and bolt straight through with the slotted 900 rubbers.

These in the pic are what i made to both move the cable bracket away from fouling the camcover bolt as you need and also to respace the rubbers to accept the wider spaced Mikuni VM32's from a 1000 Katana.





Zed you are one talented mother f’er. 
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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Re: Mikuni 26mm not fitting on KZ650 head

22 Feb 2023 08:58
#880634
Wow this is very cool, great idea. Did you makeup some gaskets to go between your 10mm plate and the head to seal it off? I’ll have to find a local machine shop for this. 

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Re: Mikuni 26mm not fitting on KZ650 head

22 Feb 2023 09:07 - 22 Feb 2023 09:17
#880635
sflesch94 wrote:
Wow this is very cool, great idea. Did you makeup some gaskets to go between your 10mm plate and the head to seal it off? I’ll have to find a local machine shop for this. 
Yes! I make them from Flexoid gasket material.
Genuine Flexoid® Gasket Paper Material - 500mm Wide Rolls - Various Thicknesses | eBay
 
AIR CORRECTOR JETS FOR VM CARBS AND ETHANOL RESISTANT VITON CHOKE PLUNGER SEAL REPLACMENT FOR ALL CLASSIC AND MODERN MOTORCYCLE CARBURETTORS
www.kzrider.com/23-for-sale/611992-air-c...lide-mikunis?start=0





Last edit: 22 Feb 2023 09:17 by zed1015.

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Re: Mikuni 26mm not fitting on KZ650 head

22 Feb 2023 12:50 - 22 Feb 2023 12:51
#880640
It does not look like your too much off. You could hand file some stock off the cam cover and bracket where its hitting.



I did not have to do anything to mine to get them to fit.
 
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: 22 Feb 2023 12:51 by Injected.

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Re: Mikuni 26mm not fitting on KZ650 head

22 Feb 2023 16:52
#880647
Do you have a picture showing your throttle cable mount assembly? Weird yours doesn’t hit, and I need around 1/4” of clearance. 

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