carburetor top end adjustment

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421SmQQthie

New Member
Feb 6, 2010
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ga
i saw a videoo and the guy used high trtemp gasket i did that i just got in my new cns carb today wooooooohooooooooo it rocks i havnt had to test it proporly yet but it has alot more power on take off spookytooth woooooohooooo
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
252
63
up north now
hi i got my cns carb today can i find on net or can you give me a place to start on the mixture?
Shouldn't the carb be set close from the factory since it is supposed to be a "high performance replacement"?

The only way to make sure your carb is set properly is to check your spark plug.
 

421SmQQthie

New Member
Feb 6, 2010
18
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ga
yea but of corse i forgot i had the choke on and messed with it loool but ill get it figured today but yea it was set to begin with im sure ill get it we got snow this morning ill go out and set it in a bit thanks
 

stv1jzgte

New Member
Feb 11, 2009
489
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australia
With the amount of differences with each motor and differences each person makes to there motor exhausts boost bottles plugs etc it would be a miracale if the same carb setting worked for everymotor 48cc -66cc
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
252
63
up north now
With the amount of differences with each motor and differences each person makes to there motor exhausts boost bottles plugs etc it would be a miracale if the same carb setting worked for everymotor 48cc -66cc
Yeah, I think they call that "electronic fuel injection".
 

camlifter

Active Member
May 4, 2009
1,033
16
36
acme labs marion ohio
when tuning the carb the needle clip settings only effect the part throttle performance, at wot the jet size is what controls the tune, almost always it is too rich. if it's sputtering and loosing power it's to rich, you'll need a smaller jet or need to solder the jet closed and drill it smaller, i almost always end up with the jet drilled to a #73 drill size for a good tune, with the needle clip in the 2nd slot.
contrary to popular belief an expansion chamber exhaust normally needs leaner jetting as the tuned pulse returns more fuel back into the cycylinder instead of wasting it out the pipe.
 

Alson

New Member
May 16, 2010
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Kankakee Illinois
Your right about the expansion chamber does make the carb run richer. I have a new style NT carb, and it jerks all the way up to 20 mph, raised the c-clip to lean it jerking almost all went away, but it was to lean. So now its only salution is smaller jet size, I heard the new NT carb jet size is 0.79 so I got to go smaller, dont know were to start
 

poorboys bikes

Custom Bike Builder
Apr 18, 2010
46
0
0
wichita, ks
if you're taking the baffle completely off, you're not getting enough back pressure from your exhaust. back pressure is a big element in any engine whether its cars of bikes. adjusting your back pressure along with your fuel flow is just as important, otherwise your blowing fuel right through the chamber to the exhaust and the motor will get too hot and start to stutter. I just started by drilling a small hole in the baffle then a lil bigger, then 2 holes and so on... My speed carbs on all my bikes work awesome! a chamber pipe will help but they also have to be set at the right length for you to get the band in the area you want! you can dial in your exhaust alot easier with the stock pipe without the need to cut/add, weld, and find ways to mount it! you just have to fiddle with everything til one day you get it!!!