Moped Army

So since I built this PA-50II It has always had a take-off problem. At first it Idled normal but give it too much throttle at take off and it would bog and bluuuhhh.
I would have to peddle all the way through an intersection while feathering the throttle till I got up to about 10 mph
Before it would finally start to build speed on its own, then it seemed ok up to 45.

I should mention the build is:
70cc DR kit
21mm delorto jetted to 95
proma circut pipe

I lived with the condition for about a week , then the Idile jumped way up and I couldnt turn it down.
I asked on MA and people said "air leak".
I continued to hot rod around town for another week but
of course at high speed the air leak caused a lean condition
and It started soft seizing.
So I finally had to tear it all down and find the leak.

The culprit was the Magnito side seal caused maybe by a rusty crank or bent crank (it seems to have a wobble)





So I get a new crank and build it back up proper and am back to perfect starting and idieling zone, but I'm now again faced with the weak low end stumble.
I dont know a lot about setting up this carburator and any one with a hobbit knows what a bitch carb acccess is.
so now in starting to monkey with the carb.
This needle is just how it was out of the package.



It seems to have four different graduations governed by that
c-clip. What effect if any will changing the hight of the needle
have on curing my low end bluuuhhh