Carby I bored the jet on a china carb

[Guest]

Exellent job. My hat is off to sk8freak.

augi- if you are running too rich right now, then I wouldn't drill the jet. The reason it ran better in the cold was that there is more oxygen molecules per square inch of "air", which makes for a better mixture if you are a bit rich. Once it is warmer out you may want to go up a slot on your needle. THEN if it's too lean, drill the jet.....just a tiny bit bigger.

Also, if you go with a fuel to oil mix of say 40 to 1, you are effectively making the fuel/air ratio richer. More oil makes it leaner. Does that make sense?

 

[gone_fishin]

well, i never thought i was running too rich, i'm concerned about too lean and have been trying to figure out how to get the right combo of everything for best "stock" performance...i was concerned about how it runs best leaner, how pre-mix and ratios affect octane, carb mixture, flash-point, plug gap...man oh man oh man....

anyway, i remember reading about how one version of the chinese engine was gonna have richer port-timing...that got me to thinking along a new line...

i've optimized airflow, full breather intake and no exhaust baffle, but the muffler is capped with the reduced outlet. so, my engine's ports are likely timed on the lean side, because she screams when cold. that's the problem, it sounds smooth but too dry.

i knew i needed more fuel, and prolly more pre-mix, but i was confident with 36:1 real oil. it hit me...now that everything else is right, bump the needle one slot richer (3rd down). i get a good start, kind of a cranky warm-up, then lots of power thru the whole range, including a top-end that still has plenty of fuel to work with. and, a miniscule puff of smoke once in a while, so i know i'm not burning off all my lube. now it sounds more like internal combustion than that 2-stroke "buzz" and i'm happy i have it about as right as it's gonna get.

that's it for now, like i said "a labor of love and a work always in progress" 8)

 

[mrsaxman99]

Anyone else gonna try it? Come on, you know you want to. Even if you really screw it up, you can buy another jet cheap.

this coming from a guy that hasn't even bought one of these engines yet...

 

[Guest]

I haven't bought one yet, but I do know a thing or two about these engines (two strokes in general).

I guess you can help out here better because you have an engine?

Yeah, that's what I thought.