Master spoon is on the money ...so is mountian....I've seen a 140 shoehorned in one ...Cranga did one on here but it's a bit of a mission.Don't know if i'd bother with the irk and oilslinger either ...sort of polishing a turd (no offence) but the Ducars don't handle it too well without a few mods like porting and a high comp piston etc etc that'll push you up to $300 easy ...if ya do it right ...if ya don't it won't run for long.
Anyway here's some other mods for em I think are important
SUSPENSION ....even the top level,high end suspension coming outta china have **** oil...first thing too change, the rebound will be shot in ya forks in a month if ya don't.
AXLES.....ya got 12mm axles which bend at the slightest hint of abuse so ya need to upgrade to 15mm if ya wanna jump it.
Crankin has had his out to 50 off a freestyle ramp..but he has a BIG downey and mad skills...but yeah he made these mods first.