ATC 200 acelleration problems

[toyota200x]

My neighbor has a 82' atc 200 and when he acclerates it studders and barley goes. He has never cleaned the air filer which is really sad and I told him to do that, but what else do you think could be wrong? Thanks

[J.D.]

Old gas, clogged carb, screwed up sparkplug(buy a new one)

[200x Basket]

it sounds like proper maintenance is the problem. kick his ass and sell the trike to a real triker