Diagnose too lean or too rich on 2 stroke

[Ati]

Been searching quiet a lot and still bit stuck with it, not too sure wether bike is running rich or lean, or good,

Last time I checked spark plug it was blackish, mainly black (Rich)

1st Kickstart with choke on and gets too really high rpms, without choke does not turn on (Rich)

A lot of smoke coming out when starting (Rich) but than settles, (Lean/Rich?)

No fluids coming out of exhaust ()

Bigger power output at higher rpm

When stoping at lights, idle stays middleish than drops down after a while (Lean)

Less power when runs for a while (Lean)

Runs better when choke applied at high rpm but when gets down stalls (?)

Does NOT backfire (Rich)

Normal smoke coming out (Lean)

Idle tends to be at lowest when lights are applied at night time.

The needle is set to the lowest point

Have an aftermarket airfilter.

Need help of what I should do to gain more performance or stay with it, what I should change etc, or if any dealers would be able to diagnose what to change.

[Mr Fro]

Get it on a dyno. Sounds like you need to up the main jet and turn in your idle screw.

[Gadgey]

Theres a kit called or used to called "Colour Tune"

It allows you to watch the combustion through the spark plug and therefore can tell wether its running rich/lean etc.

I dont know if its still made but sounds like it might help in this situation.

[eastanglianbiker]

personally i would set the needle to centre setting then turn mixture screw right in so you have a starting point turn mixture screw 1 1/2 turns out and see how it runs that is a basic set up setting and a good base to work from as you can give it another half turn in or out easily to check how its running,and its normally for bikes to need choke to start in cooler/colder weather and the revs will always be higher due to the fact its getting less air /more fuel.running at high rpm and putting choke on will cause it to die as you are flooding the engine with to much fuel not enough air,the only time you wouldnt have the problem was if it was running to weak in the first place