short story: 3 four stroke 250 bikes, same chinese seller, same color, same box, same order, same everything.
all three require different jetting, one had a hole in radiator and the hose wasn´t in place, other had a so bad engine casting that the water pump was sealed on in and out pipes. one of them doesn´t carry engine oil, one had the rear shock stuck, wouldn´t move at all. one had not have the valve timing correct, i could be here all day long. :rotfl:
BUT, i had have good luck with the keihin pwk copies. they are cheap, jets and needles readly available, even slides are cheap, and carbs are very consistent. we run them a lot on moded dt 50´s yamaha and a lot of other small bikes, like scooters, and they are very good.
actually i am running one 30 instead of stock 26 pe keihin on my cr 80 and it would put the old and weared stock one to shame in ease of tuning and part throttle openings.
there are several brands and most scooter parts shop have them on 24, 28, 30 and 32 sizes.
just to conclude, we have a mx amateur class that consists in original 50cc engines but modded at will!!!! the displacement could be as big as we can get and the bikes can be whatever we want. most run these carbs... :cool:
now, chinese jets are another different matter :think: