can't figure it out

GoldenMotor.com

cozmo_not

New Member
Feb 6, 2013
5
0
0
Raleigh
so i have the engine installed and it was working fine for about 3 weeks. accidentally burned some 4 stroke oil in the motor, had to take it apart, decarbonize the head, and i got a new exhaust pipe and everything. now it runs for about 30 seconds normally, but as soon as it gets warm it wont rev up to half what it used to and there is no power. not even enough to keep it running with the clutch engaged. checked the fuel filter., even rode it with no gas cap to see if it was a problem with that. nothing worked:-||. http://motorbicycling.com/images/smilies/Waa.gif


please help, im using this thing as my main ride and i have cabin fever from staying home all the time.
 

wan37

Member
May 29, 2011
354
4
18
Illinois
Help you solve the problem,well what engine is it and what carb too?Then will go from there.
 
Last edited:

cozmo_not

New Member
Feb 6, 2013
5
0
0
Raleigh
loosened the choke cable and that helped a little bit but it still has no get up and go like it used to. it sounds like its barely turning over and running about idle speed at full throttle.
 

dracothered

New Member
Jul 25, 2012
973
1
0
Howell, MI.
how would i go about cleaning the carb?
Well I've never taken one of those carbs apart, but it can't be much worse than what they use on a Tecumseh 2 stroke. You would have to open up the carb to its basic components and spray it down with carb cleaner and clean all the passages. Then replace anything that needs to be replace. After that put it back together and re-tune it. First start with the fuel filter by replacing it, then go to cleaning the carb if you need to.
 

crassius

Well-Known Member
Sep 30, 2012
4,032
158
63
USA
I'd pull the barrel & see if that motor oil packed up your rings or glazed your cylinder.
 

cozmo_not

New Member
Feb 6, 2013
5
0
0
Raleigh
already cleaned all the inside. i fiddled with the idle/fuel mix setting and now it will run great for about 2 minutes and then suddenly loses power and revs. also when i pop the clutch to start the motor there is a second where the chain is turning but it seems like the engine isn't. then it catches and starts.
 

BigBlue

Member
Nov 29, 2011
781
0
16
California
Get rid of the CNS carb and buy yourself a NT carb off Ebay. Clean your intake manifold. Replace or clean the spark plug.

Hopefully you torqued your head with a torque wrench or you maybe loosing compression.

Good Luck,

Chris
AKA: BigBlue
 

Groove

New Member
Nov 2, 2012
245
2
0
Lexington, KY
I don't think you have a serious issue. It sounds like you have an air leak (vacuum leak). Check the intake manifold and other areas prone to leaks. Then you should be good to go.

-Groove
 

crassius

Well-Known Member
Sep 30, 2012
4,032
158
63
USA
That would be called the cylinder jug, not the barrel. :D
many apologies, I'm old and started doing this when cylinders were all made by gun manufacturers that had the best equipment for boring straight & true (BSA & Royal Enfield come to mind)
 

nightcruiser

New Member
Mar 25, 2011
1,180
2
0
USA
how would i go about cleaning the carb?
First question I have is what kind of air filter do you have on your cns carb? If you have the red plastic filter the first thing you want to do is pull the filter and wash out the foam insert, they are notorious for clogging up from blow-back and screwing up the air/fuel mix (making the motor run rich when clogged), if you have the cone style high flow filter this shouldn't be a problem.

Cleaning the carb is pretty easy. First pull the two screws off the top that secure the cables, then pull the cables, slide and enrichment jet plunger out of the carb (just pull straight up). Remove the air filter if possible, you don't want it to get soaked with premix fuel and get clogged up. Then loosen the carb neck and slide the carb off. At this point you can pull the drain screw from the bottom of the bowl to drain out fuel (if you want). Then just pull the 4 screws out of the bowl and split the bowl from the top half of the carb. Now just blow the inside of the carb out with carb cleaner, there are 3 jets in the CNS carb, the main jet, the idle jet and the enrichment jet, make sure you blow them out well. Pay special attention to the idle jet, the opening in it is very small and sometimes the force from the flow of carb cleaner isn't enough to clear it out, I usually run a thin wire (like the wire from inside a twist tie) through the idle jet to make sure its cleared out (don't force anything in there, use something that fits through easily). If you want you can pull the float and blow inside the needle valve housing clean, or you can probably get away with just blowing carb cleaner down the fuel inlet to force out any crap that may be in the needle valve. Then just reassemble the carb.

When you install a CNS carb keep in mind the that they have a rubber seal in the neck of the carb, this seal is formed to fit over the end of the intake. When you install the carb push it down until is seats all the way on the intake, then wiggle the carb around a bit while pushing it on the intake, this will help get the intake seated into that seal (before you do this you might want to pull that seal out of the neck of the carb and fit it on the end of your intake, just to get an idea what you are dealing with, once you see how it fits you should understand what you need to accomplish when mounting the carb). Finally, when you are tightening the screw on the neck of the carb make sure you are pushing the carb firmly onto the intake to make that seal. If you do it this way you wont have any air leaks. When you insert the slide into the carb note the slot on one side and make sure it goes over the pin you see inside the carb, otherwise it wont go down into the carb like it should (the enrichment plunger can go in any which way, it has no slot to guide it)
 
Last edited: