A CNS48 Hack

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rustycase

Gutter Rider
May 26, 2011
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A CNS48 Hack


At least some NT carb parts will interchange into the CNS48 carburetor.

Though it is the same length and configuration, the NT slide is a smaller diameter. The CNS48 slide measures .625 inches, and the NT slide measures

.5015 inches in diameter. They will not interchange. The slide cut-away angle is quite similar on both of them.

The needles for low/mid-range are different also, but they WILL interchange.

The NT needle is longer by 2mm, and has 4 e-clip grooves, though the base

measurement is identical.
The CNS48 uses 5 e-clip grooves, one of which is lower than #4 on the NT.

CNS base @20mm @25mm @30mm (measurement down, from top of needle)
.075 .070 .069 .062 (these measurements in inches)
NT .075 .073 .065 .063 (as above)

Following another prior experiment with the CNS, I have installed an NT needle in my CNS48 and it performs well.
Perhaps an improvement, yet nothing notable. (My motor has other issues.)

It appears, the particular NT needle I tested, should run a bit leaner at both the beginning, and end of it's control range, especially considering it is 2mm longer. It would be richer in the middle of it's control range.

I have not yet tried the CNS48 needle in an NT carb.
I have also not compared these needles to other NT and CNS parts.

(Sry for mixing SAE and metric measurements.)
rc
 

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