66cc HT CNS Carburetor Issues

[Down_n_Dixie]

I'm running a skyhawk 66cc motor with the upgraded performance carburetor. When I pulled the carb out of the box It had an assortment of tubes running across it (pics included). One of the tubes is literaly about an eighth of an inch long, burnt and pinched by whoever boxed it to seal the vent off. When I first Ran the bike it was running Very lean and and bogging down when I opened the choke, and no amount of tuning the idle and air mix screws fixed the problem. I found the culprit, if you look at the pic you can see black tape on the perimeter of the air filter where I covered several holes which seem to have no purpose. Now it runs with the choke open and pulls great but, IT runs EXTREMELY rich, at one point There were flames coming out of the exhaust so I killed it and got off for fear of an explosion lol, but the engine was not overheated so I attribute that to the rich mixture. So after that brief of my situation my QUESTION is, Do these tubes seem correct? And how to correct it if not. Also, is the rich condition the result of not enough airflow due to these tubes? i;ve had no luck leaning it out with the screws and i have the clip set the the second from the top of the needle. ONe last tidbit of info, The engine also does not idle unless I open the throttle slightly. Am currently using 16:1 for the break-in Sorry for the wall of text guys, If any of you make it to the end Any advice would be greatly appreciated. THANKS

Pic Info: The plug shows the dark and oily rich condition indicator.
and the carb pic shows the funky tubing on this thing. Sorry
for the quality I have no macro setting .

 

[goodtime65]

They say that the small tube that runs from the top to the bowl on the carb has to be connected, but if you take a real look into it you will see that the fiting on the bowl actualy is an over flow from inside, so that if you carb floods it will not fill your engine. The top of the carb is a vacum so to me this will pull fuel from the bowl causing a rich mixture. Iv'e only been able to get mine running good without the hose

 

[HeadSmess]

that tube really does look like it should be two tubes...

top is the vent/breather for the bowl. you want this hose to stop crud getting in there... but to let air in still.

the bottom tube is just a drain for the overflow and when you drain the bowl...

also makes it very easy to check fuel height in the bowl, that hose does

 

[goodtime65]

the top hose that you have going to the bottom is a suction. If you look the little brass fitting goes right into the throat, when the air passes by it will create a low pressure causing a vacum. The fuel in the line will be sucked up causing a very rich mixture

 

[Down_n_Dixie]

Ok, So I should disconnect the long tube, I will try this once I put the carb back on the engine. I ended up taking the carb apart and I found that the float does not fully seal off the gas intake when it is floated as high as it can go. It seems the float was installed upside down.... So I corrected this and it now functions properly, hopefully this will help as well. Also the port that is covered and sealed by the burnt tube seems to be the vent for the air/gas mixture screw, so by being sealed it pretty much makes the screw useless am I right? And why would they seal it off then?? I took that off as well. Now im off to test run my bike, hopefully these adjustments will lean out the mix. Thanks for your help so far and I will post my results when I get back. Oh and maybe that explains why I had no results adjusting the screw in the beginning.

 

[goodtime65]

The sealed off tube is a vent for the bowl, these 2 should be open. If you remove your air cleaner and look at the front of the carb you will see the idle air inlet on the right. If you look in you will see the needle

 

[Down_n_Dixie]

Goodtime, When I unseal the vent for the bowl my Bike shows all the signs of running too lean, bogging on open throttle and dying when i open the choke. If any of you are currently using one of these carbs effectively could you please post how you have yours set up? (tubes, needle level, mix screw settings, etc.) Also I seem to have noticed a variance in these things, some have a larger airfilter cone and some have smaller ones with holes punched on the bottom perimeter, whats up?

 

[skrufryder]

well my carb dosnt have any tubes on it...i was advised by the company I bought it from to remove them....needle is on the lowest setting.....My bike runs much better on a sunny 70's day as apossed to 50 and raining.... The weather here is all over the place in just one day you have to adjust almost every time you ride....

 

[HeadSmess]

ahhhh atmospheric tempers.... these engines really do have their moments

 

[Down_n_Dixie]

quick update: So I unplugged the float overflow tube from the top and am letting it hang, also removed the tape so more airflow could come thru and took off the burnt tube as it seemed pointless. No noticeable pwer increase and the mix is still rich even with the clip all the to the leanest setting! Its quite discouraging to be putting around at 15-20 mph tops whle my buddy is zippin around doin 30 on his 50cc and stock carb I cant seem to figure this out.
Well I've almost done with my second tank of gas so maybe if I up the mixture to 32:1 it might help out what do you guys think?