Cr 29's

Any opinions on Cr 29's on a comp built 1075. Negatives and positives?

Depends on the build. If it is a fairly mild build, they should  be pretty excellent. If it is a big port, high compression, radical cam build, they will be inadequate.

wrote:

Any opinions on Cr 29's on a comp built 1075. Negatives and positives?
 

Comp built? for what purpose?

Not enough information given to reply with any suggestions or advice, please elaborate.

Injected , per your enquiry.  1075cc street build. 205 PSI dome piston mtc compression. PSP 3x cams, ported intake and exhaust. Welded crank, 4-1 Vance Hines. APE springs. Earls 16 row curved oil cooler. Back cut trans. I'm sure I missed something. Full PSP build by Joe Hooper. Currently running 28mm Mikuni jetted, pods and Zed1015 air correctcorrector jets. K+N pods.

wrote:

Injected , per your enquiry.  1075cc street build. 205 PSI dome piston mtc compression. PSP 3x cams, ported intake and exhaust. Welded crank, 4-1 Vance Hines. APE springs. Earls 16 row curved oil cooler. Back cut trans. I'm sure I missed something. Full PSP build by Joe Hooper. Currently running 28mm Mikuni jetted, pods and Zed1015 air correctcorrector jets. K+N pods.



 

Thanks for the more comprehensive information.
Zed1015 may have more experience than me on this combination but I will take a stab at it.

You did not mention what head was on it or if it had oversize valves but it may not matter.

I believe the general rules use to be like this :

If it was a hot 1015cc you would want at least a 29 smooth bore.
If it close to 1200cc you would want at least a 33 smooth bore.

Your sort of in between so I would say the 31 CR Keihins may work for you, the 29 version may be a bit small for those cams/head.

The cheaper solution would be to bore the 28's to 30mm and open up the orifices where the fuel flows between the carb bodies. You also want to use the largest float needle valve assembly as that my also be a fuel restriction. WGcarbs was selling these assemblies but I don't see it listed on the web site.
We know the Mikuni VM carbs work very well and almost bog free, the same cannot be said about 33 smooths and 34 flats - they do have a bog but it takes a lot of effort to tune thru it.
You already have the air corrector jets so maybe expand on that and see if it likes it.
 

Forgot Dyna 2000 set half way between . Running too far advanced she pings.

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Forgot Dyna 2000 set half way between . Running too far advanced she pings.

 

38 degrees of total advance is a maximum suggested setting for these engines (for a drag race motor its only 2 deg higher)
On the street you run the chance of damaging your engine with maximum settings as race motors don't run for very long.

It may be a tiny less "snappy" but you have a ton of motor there for the street.
I am currently building a 1197cc KZ street motor and I think I will limit it to 36 degrees.
 

Injected, All response very much appreciated and any more welcome. I may be old but I still like to twist that "Loud Handle"