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Best size Carbs?

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510racer
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Best size Carbs?

#1 PostAuthor: 510racer » Tue Dec 16, 2014 1:58 am

Looking at a new set of Keihin CR carbs for my Z900.

Are 29's best suited to standard bore 900 or would you go something slightly larger?

Thanks.
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Jay1969
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#2 PostAuthor: Jay1969 » Tue Dec 16, 2014 3:45 am

Any larger than 29mm runs the risk of over fueling standard Z900 head.
The Keihin CR special's CAN be difficult to dial in spot on as it is,
without extensive dyno runs, however, an experienced
race techy would set them up a doddle, compared to the average novice (like me).
They are simpler to work on than the standard Z900 26mm Mikuni's
though, especially setting the needle heights!

~Jay.
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510racer
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#3 PostAuthor: 510racer » Tue Dec 16, 2014 5:14 am

Thanks for that Jay.

Sounds like you've had experience with both, so could you please tell me one more thing: Do the Keihin's run the same push/pull throttle cable linkage?
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#4 PostAuthor: Ginger Bear » Tue Dec 16, 2014 8:06 am

Jason,

Is this something you've actually experienced?
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#5 PostAuthor: martinz1000r » Tue Dec 16, 2014 9:40 am

you will need a twin cable push/pull type throttle. I ran CR29 on my 1260 Z900 at Cadwell last year and it ran out of steam at the top end so now running CR33.
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#6 PostAuthor: chrisNI » Tue Dec 16, 2014 9:41 am

510racer wrote: Do the Keihin's run the same push/pull throttle cable linkage?


I don't know if all CRs run the same linkage but some come with Z1/Z1000 on the box and they bolt straight on linkage and all.
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#7 PostAuthor: nzphil » Tue Dec 16, 2014 9:51 am

I've just ordered a set of CR29's from Dynoman in the US, the owner Buzz was very helpful, I've also ordered spare jets, one size smaller & one size larger.

http://www.dynoman.net/carb/keiCR.html#cr29s


Hope they arrive before Christmas :D
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Most of my money has been spent on Z's, beer & women,
The rest has been squandered.
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#8 PostAuthor: Jay1969 » Tue Dec 16, 2014 11:01 am

510racer wrote:Thanks for that Jay.

Sounds like you've had experience with both, so could you please tell me one more thing: Do the Keihin's run the same push/pull throttle cable linkage?

Yes, like chrisNI was saying,
just hook up push/pull throttle cables like you
would on your standard carbs. I bought CR 29's for my Zed
from Allens Performance, and straight out the box already had the linkage fitted for the standard throttle cables.

~Jay.
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#9 PostAuthor: garyd » Tue Dec 16, 2014 11:28 am

The CRs will perform best it you pep up the head with some cams etc.
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nw66
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#10 PostAuthor: nw66 » Tue Dec 16, 2014 11:44 am

Had a set of Cr 29's on my standard 900 after a needle change as was running a bit weak ran a treat!! you will need a push/pull throttle I use motion pro basic but work well. Allens performance good guys!!

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nw66
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#11 PostAuthor: nw66 » Tue Dec 16, 2014 11:49 am

nw66 wrote:Had a set of Cr 29's on my standard 900 after a needle change as was running a bit weak ran a treat!! you will need a push/pull throttle I use motion pro basic but work well. Allens performance good guys!!
Was running with an open 4/2/1

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Suzuki Katana 1170 Homa sz

Yamaha R7/R1 motor

Kawasaki ZXR750R M1

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#12 PostAuthor: snotie1965 » Tue Dec 16, 2014 2:07 pm

martinz1000r wrote:you will need a twin cable push/pull type throttle. I ran CR29 on my 1260 Z900 at Cadwell last year and it ran out of steam at the top end so now running CR33.
Hi martin, have you still got your old 29`s ? if so ,do you think they would be suitable for my uni-trak with 1170 wiseco ? or should i go bigger ?
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#13 PostAuthor: london calling » Tue Dec 16, 2014 3:01 pm

36mm RS Mikuni flatslides are a good choice for an 1170 motor :wink:
Maybe 38mm if you have head work such as larger valves,porting,gas flow,etc.
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nw66
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#14 PostAuthor: nw66 » Tue Dec 16, 2014 4:21 pm

I have rs 36's on my Katana 1170 with head work cams they work really well loads of grunt go to big it pushes it to far up! tuned by Chris at Grumpy 1260:)

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Last edited by nw66 on Tue Dec 16, 2014 4:39 pm, edited 2 times in total.
Ducati 1199R Race

Ducati 1198R Race

Suzuki GS/GSXR1216 Turbo Drag

Suzuki Katana 1170 Homa sz

Yamaha R7/R1 motor

Kawasaki ZXR750R M1

KTM SXF250







The older it gets the faster it was :-))
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#15 PostAuthor: garyd » Tue Dec 16, 2014 4:21 pm

I've got 38s for my 1170 which does have a flowed head, big valves and lumpy cams
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