How Do I Tune a 2 cycle engine?

[Guest]

what are these 2 screws for on the engine and how do i tune them? the one next to the choke is small and black and the other one is bigger and yellow/gold-ish color

black screw^

bronze-ish screw circled^

Edited August 30, 2009 by Krannyman92

[newls1]

That might be your needle and seat adjustment for the carb....... If it is anything like tuning a Nitro RC 2 stroke engine...think of it this way: Counter clockwise for "RICH" and Clockwise to "LEAN" it out. I think of it like turning on your outside water spicket..........

[Guest]

That might be your needle and seat adjustment for the carb....... If it is anything like tuning a Nitro RC 2 stroke engine...think of it this way: Counter clockwise for "RICH" and Clockwise to "LEAN" it out. I think of it like turning on your outside water spicket..........

cool. but what does which screw control. the needle and seat adjustment that you talk about.

edit: and is there a reason why there was some blue smoke coming from the exhaust (using old gas i dont know if that matters) versus a new tank of gas? does it matter on how much 2 stroke oil you use or something?

Edited August 30, 2009 by Krannyman92

[newls1]

what is your oil mixture?

[Guest]

what is your oil mixture?

that i dont know. the gas that had the hint of blue smoke my god father put in. he said to just put a cap full of oil or two to a full gas tank. which i did, but i put 3. i couldnt find any stats on the bike or the engine. but the engine looks to be a standard 35cc or 40cc engine.

[HPI_Savage25]

Alright see if it has a mixture ratio on the gas cap or something.

Most of the time they are either 25:1, 32:1, or 50:1.

The smoke is fine, and unless you buy the smokeless oil you want to see some smoke IMO, you know it is getting lubricated.

As far as the tuning goes, their isn't a exact tuning for it. With weather changes, different locations, humidity and such will throw the tuning off. Does it run good now or what?

[Guest]

Alright see if it has a mixture ratio on the gas cap or something.

Most of the time they are either 25:1, 32:1, or 50:1.

The smoke is fine, and unless you buy the smokeless oil you want to see some smoke IMO, you know it is getting lubricated.

As far as the tuning goes, their isn't a exact tuning for it. With weather changes, different locations, humidity and such will throw the tuning off. Does it run good now or what?

no mix ratio on the cap...its one of those brandless bikes if that helps.

on the original tank, it hit about 20mph on the speedo then 40 right before i ran out and i had to walk it home to put more gas/oil in it.

but it was dropping to around 15 or so after the new fillup. a neighbor kid was riding his little pocket bike around and he messed with the screws a little and i went around 25. i noticed he had some blue coming out of his exhaust but none out of mine...i dunno if that helps.

i looked on his bike for a gas mixture since he had the same exact engine as mine but i didnt find anything.

Edited August 30, 2009 by Krannyman92