after market high preformance carb help

GoldenMotor.com

westy

New Member
Jun 26, 2014
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hey all I just got a new high performance carbie and im wondering what are all the open vents for I know one on the bottom is for fuel to come out off but what are the rest for. and Im having trouble the bike runs and idles but it seams sluggish and I have a fair bit of fuel coming out my run off value ideas cheers
 

2door

Moderator
Staff member
Sep 15, 2008
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Littleton, Colorado
This is why I dislike sellers who attach words like, 'high performance, 'race' and 'speed' to their products. Novice builders see those words and believe them and buy a product that probably isn't any better, or even as good as what they have already.

We might be able to help you if you can give us a brand name or type of the carburetor. It sounds like a Walbro or a Chinese knock-off of one. "High Performance" doesn't tell us much. Post a picture of the carb. That will help us help you.

Tom
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
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Central Area of Texas
Sounds like you have a CNS carb.



If it is like most other carbs, the main jet is to big and your engine is running very rich and being so sluggish because it is 4 stroking terribly.

Reducing the size of the main jet is normally the cure for this problem if in fact that is what you have going on.

Map
 

westy

New Member
Jun 26, 2014
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map bike is spot on that's the carbi noob question how can it be 4stroking if its a two stroke?
 

mapbike

Well-Known Member
Mar 14, 2010
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Central Area of Texas
map bike is spot on that's the carbi noob question how can it be 4stroking if its a two stroke?
When a 2 Stroke engine is running to rich on fuel it will start firing every other stroke rather than on every stroke, you know it's 4 stroking when power is down and the engine makes a blabbering sound rather than a steady buzz.

It sounds like what you will need to do is reduce the size of the main jet in the carb and once you get that right you'll likey see the power go up and the engine will run like it should.

map
 

xseler

Well-Known Member
Apr 14, 2013
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OKC, OK
My CNS V3 also has "EPA" stamped on the bowl ---- which I find amusing, because it certainly used much more fuel in it's stock form and didn't run as good.

I've reduced my jet size considerably. I've also removed that brass plug by the air filter (it has a second adjuster needle beneath it that needs to be accessed).

 
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mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
My CNS V3 also has "EPA" stamped on the bowl ---- which I find amusing, because it certainly used much more fuel in it's stock form and didn't run as good.

I've reduced my jet size considerably. I've also removed that brass plug by the air filter (it has a second adjuster needle beneath it that needs to be accessed).
I was hoping you would ring in here buddy, I knew you have had good results with your CNS carb and could give some excellent pointers on tuning it.

The CNS I have doesn't have a plug over the mixture screw but I see that the newer ones do, or at least some of them do, gasbike.net shows several models of the CNS and that is wwhere I remembered seeing them so I went there and cobbed the pic I posted here earlier.

Map
 

westy

New Member
Jun 26, 2014
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perth
how do u test the jets size you have and what do u recommend I drop it down too also are both needed to be changed the big and small one thanks westy
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
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Central Area of Texas
some of us just solder and redrill our jets instead of buying new ones and ending up with several sometimes that are never used. a cheap set of wire gauge bits, a small propane torch or cigarette lighter torch and a very small piece of solder and you can make whatever jet size you need in just a couple minutes using the one stock size jet.

map