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Discussion Starter · #1 ·
I am considering flatslides for my ZX7 I have heard nothing but good things and that they really increase response for a ZX7.
I am assuming the best size is probably going to 39 mm as opposed to 41 or larger.
I have looked at a couple of sites and it seems these are pretty hard to get... I have gone out to the Mikuni site and don't see 39mm flatslides
I see
Mikuni Rs Series Carbs 34Mm, 38Mm, 40Mm
But no 39's
Anyone running flatslides and can point me to a place that has these? Would also be open to used set

Thanks
Todd
 

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1993 Zx-7 L Model, 2006 ZX-10R
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Kawasaki had Keihin FCRs from the factory. Sudco sell FCRs for the ZX7R.
$$$$. Last time I looked at a set of FCRs on the used market, they were $1500.
 
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39s are just 40s with a 1mm sleeve in the carb bore, & I think they would be too big a carb for a 750. My 1983 Highly modified CB1100F ran 39s.....
 
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‘83 Gpz750 Resto-mod, ‘78 Kz1000 Resto-mod, ‘18 Z900RS
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The Mikuni RS flatslides are NOT a direct replacement to the Keihin FCR’s. As far as I remember, there are no kits for “downdraft” heads only side drafts for the RS series.

Later, Doug
 

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39s are just 40s with a 1mm sleeve in the carb bore, & I think they would be too big a carb for a 750. My 1983 Highly modified CB1100F ran 39s.....
There is a thing called over-carbing an engine. I never looked into why KHI went from 39mm to 41mm between the M and N models.
 

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Discussion Starter · #9 ·
I am not going to race this bike... This has always been my dream bike. Second one I have owned.. not letting this one go! I just want a bit more snap when I turn the throttle. However,
1. I can't find ANY flatslides for a 2003. I have gone to the Mikuni site and Sudco. They don't even list the ZX7R
2. My buddy ran 39mm on his GSXR and it was absolutely amazing the difference between CV and FCRs
3. However, is it worth $1800 for a set of carbs ?????

I thought I saw someone say they saw FCR for ZX7r from Sudco.. I have been all over that site and don't see them anywhere

Todd
 

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Discussion Starter · #10 ·
I am not going to race this bike... This has always been my dream bike. Second one I have owned.. not letting this one go! I just want a bit more snap when I turn the throttle. However,
1. I can't find ANY flatslides for a 2003. I have gone to the Mikuni site and Sudco. They don't even list the ZX7R
2. My buddy ran 39mm on his GSXR and it was absolutely amazing the difference between CV and FCRs
3. However, is it worth $1800 for a set of carbs ?????

I thought I saw someone say they saw FCR for ZX7r from Sudco.. I have been all over that site and don't see them anywhere

Todd

Here is what I usually find : NOS Keihin FCR 39 flatslide racing carburetors / Kawasaki ZXR750R ZX7R - Frank! MXParts (frankmxparts.com)

but even these don't seem to fit my bike
Details:
  • NOS downdraft Keihin FCR39 flatslide racing carburetors
  • with double accelerator pumps
  • with choke
  • including airbox adapter
These will fit:
  • the 1991-1992 Kawasaki ZXR750R (K1, K2)
  • the 1993-1994 Kawasaki ZXR750R (M1, M2).
 

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1993 Zx-7 L Model, 2006 ZX-10R
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5,026 Posts
I am not going to race this bike... This has always been my dream bike. Second one I have owned.. not letting this one go! I just want a bit more snap when I turn the throttle. However,
1. I can't find ANY flatslides for a 2003. I have gone to the Mikuni site and Sudco. They don't even list the ZX7R
2. My buddy ran 39mm on his GSXR and it was absolutely amazing the difference between CV and FCRs
3. However, is it worth $1800 for a set of carbs ?????

I thought I saw someone say they saw FCR for ZX7r from Sudco.. I have been all over that site and don't see them anywhere

Todd
Yes. Once you get the carbs dialed in. Totally worth it.
 
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Font Material property Parallel Number Screenshot


From Sudco's catalog
 

· 7777
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Yes. Once you get the carbs dialed in. Totally worth it.
I totally disagree, and I've had many flatslides. They are a pain in the ass. I have a set on my M and wonder if I'll ever put fuel through them. They are best at WOT, or if you learn to manage the throttle. Heaven forbid you let old fuel sit in them for a month or two. Keep the CV's for the street.
 

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I totally disagree, and I've had many flatslides. They are a pain in the ass. I have a set on my M and wonder if I'll ever put fuel through them. They are best at WOT, or if you learn to manage the throttle. Heaven forbid you let old fuel sit in them for a month or two. Keep the CV's for the street.
To each their own. FCRs for street use aren't that bad. But, like you said, you have to manage the throttle. As far as that goes, it wasn't difficult for me to switch from CV to FCR. Just have to have the mindset that you are in control of how much air you're allowing into the engine at various rpms and throttle actuations. E.g. you don't want to immediately use WOT from a complete stop. You gradually roll the throttle to WOT.
 

· 7777
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To each their own. FCRs for street use aren't that bad. But, like you said, you have to manage the throttle. As far as that goes, it wasn't difficult for me to switch from CV to FCR. Just have to have the mindset that you are in control of how much air you're allowing into the engine at various rpms and throttle actuations. E.g. you don't want to immediately use WOT from a complete stop. You gradually roll the throttle to WOT.
I got used to it, just not worth the money or risk of having to clean them or tune them for the street. $1500 for one or two horsepower is not good money spent, says the guy that has more bling everywhere on his bikes. And yes, both of my ZX7R's have flatslides.
 

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I understand your point
 

· 7777
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I've always wanted to weld or epoxy a cam position sensor bung on a ZX7R valve cover and insert a CPS and a cam pin from a ZX6R. Then adapt the ZX7R harness from one to fit a ZX7R. There are several throttle bodies that could be fitted to the ZX7R. Build a bridge above the stacks for a fuel rail and secondary set of injectors. The newer ZX6R ECU could be flashed to lower the rev limiter and tune in the injectors. It can't be that hard to adapt a ZX7R alternator/wiring. This sounds like such a better solution than batch injection like others have suggested, and fairly cheap.

I love to do Frankenstein stuff, I just never got to this one on a ZX7/R.
 
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