250r winter rebuild a few ?s

[step869]

i tore down my 86 250r for a winter rebuild frame ended up being junk i replaced frame with a 89r frame and swinger

i up graded to a 38mm carb (not a air striker)
is there a adaptor i need to mod this to fit to air box???????
and what jetting/gearing should i run with esr type 5 pipe and silencer???????
20"rear tires on 9" rims
21" front tires on 10" rims
i am very low sea level

i also have a problem with my kick starter slipin and not grabing i pulled cover dont see any worn items......what causes this????

thanks for any help,
john