Air Screw

how many turns shall i turn out the air screw?(70cc,19mm carb)

There is no set amount, you have to adjust it so it work's with your set up.

but sm1 said 3 and half turns(not full turns) its the best for every setup

no, 1 and 3/4 is where it should be.... ajust it so it idles the quickest you can get it to... if the screw is between the slide and manifold then its a fuel screw, so out means ore fuel, if its between the slide and the air filterthen its an air screw, so out means leaner... once you have the bike idling as fast as it can, note the position of the screw (so wind it back in fully and count the turns) if its a fuel screw, andits more than 1 and 3/4 out from fully in it needs a bigger pilot jet... if its an air screw and needs more than 1 and 3/4 turns out you need asmaller pilot jet... the same is reversed for less screws in than 1 and 3/4... 1 and 3/4 is the set range.. its the usual position the carb SHOULD run bestat ONCE the pilot jet is sorted... not a day go's by I don't here "but blah blah said this" I couldn't care about what blah bah said.. its wrong.

Had my air screw 3 turns out(not full turns) and when i did 4 turns out it was much more different(better acceleration).After riding a while i had ignition problems it was like the spark plug was getting oiled too much

have the same problem with mine, unsure where its meant to be set, got it so bike runs ok and have a bigger jet in the carb now as im using a race air filter. i havent been able to ride it far enough to see how it runs after a couple miles..

bet i breakdown on the way to its mot ha ha ha