Hello

My brother bought a Maxim 150 quad. Been having problems with the carb. The pilot jet is completely plugged.
Where can you buy new jets for these bikes?

The engine looks like a honda xl125, same style. Standard clutch.
Quick picture of the idle jet

 

you can take it to a dealership and see if they can match it up. OR, soak it in carb cleaner. some folks use a stiff wire or something similiar. i use an oxy acetylene torch tip cleaner pack because it is more rigid, small, and has file etchings that help. run it through the orifices and down the throat/middle of the jet. use compressed air also. make sure you see daylight through all of the orifices and down the center of the jet. then you'll know it's clean. THEN, make sure you got a fuel filter. that'll help.