Inside the 2010 Grubee Skyhawk CNS Carb

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Greg58

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May 1, 2011
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sounds like you have debris keeping the needle from seating, if the bike had sat for awhile the fuel may have been old also. Go to the first post of this thread you will see the needle and seat if you haven't allready.
 
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Greg58

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May 1, 2011
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First remove the carb, on some with clearence problems you may have to remove the air filter first. remove the two screws on the top of the carb then pull the slide and choke plunger out, no need to remove them from the cables just let them hang while you work on the carb. Be careful when you turn the carb over the gas will spill out, remove the four screws and lift off the bowl. Slide the pin that holds the float out and lift out the float, check the float to see if fuel is in it if so the float is the problem. the needle is under the float near the pin, remove the needle and clean it and the seat compressed air works well if you have it. reassemble in reverse order, make sure the slide is aligned right the slot that goes from end to end is for the alignment pin the angled notch is for the idle screw.
 

Greg58

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May 1, 2011
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Ther is a small pin that holds the choke plunger to the cable, it must be centered up to fit in the carb. make sure the slide or barrel is aligned with the pin and it will go back in, the alignment pin is across from the idle screw.
 

Greg58

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May 1, 2011
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make sure the throttle cable is not pinched or in a bind. If you look in the carb with the air filter removed the slide should close all the way to the idle screw. If not the slide is in wrong or hanging up. if it goes down to the idle screw you need to adjusted the screw counter clock wise to lower the idle. Also double check the carb mounting, it should fit all the way onto the intake with no looseness.
 

michigan 29r

New Member
Sep 5, 2011
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sparta, michigan
take the rubber hose from the vent out of the carb intake flange. mine was creating a vacuum and sucking fuel from the float bowl. Then I was able to use my needle clip settings to richen/lean my carb
 

Rocksolidperson

New Member
Feb 11, 2012
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Australia
Try changing\porting the intake port and exhuast port, remeber you want to keep your sparkplug a tan\coffee colour grey\white will melt things very quickly.
 

KCvale

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Feb 28, 2010
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...the choke plunger does not fit in all the way so the throttle cable and choke plunger cap will no longer fit on.
Before taking the carb top with the cables off and for putting it back on, activate the choke lever. That will hold the choke plunger up and make it much easier to put the top back on.
 

KCvale

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Feb 28, 2010
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Phoenix,AZ
My CNS that I just bought has 3 tubes instead of the two that are shown here. the third is beside the vent tube.
I'm just wondering what the third tube is. Any ideas?
I'm having problems with the choke mechanism so I may have to ask for help soon.
I answered your question in the e-mail you sent me.
 

robujda

New Member
Mar 19, 2015
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rhinelander wi
My carb is identical. Trying to fire it up, i noticed the fuel pouring out an overflow hose. When taking the carb off, a small, 2" brass pin fell on the ground. Where might this pin go?
 

Greg58

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May 1, 2011
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That sounds like the needle , it goes through the barrel. The only other pin holds the float in the carb but is only about one inch long. By the way welcome to the forum.
 

xseler

Well-Known Member
Apr 14, 2013
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OKC, OK
I've tinkered and adjusted and sealed my CNS-V3 carb for nearly 2 years. At times I had some "Hally-Lou-Ya" moments when the motor woke up and ran like a scalded ape. I've also had times with the same settings where I've scratched the hair from the top of my head. Well.........

I finally bought an NT Speed carb (to be installed shortly). I'm thinking that simple is sure to be better. Also hoping that the bike will run acceptably at the high altitudes in New Mexico and Colorado. Didn't have the best of luck with the CNS. The NT will surely be a lot easier to adjust.