I have a 1986 Yamaha YFM225S, Moto 4. It has a Mikuni carb, but I cannot determine the model of the carb. I have seen the dimension tables for the round slide VM series carbs and mine does not fit any of the listed dimensions. Taking into account the accuracy of my $5.99 caliper, the intake ID is 37 mm and the flange side ID is 29 mm. The flange bolts are 53 mm center to center. Does anyone have any ideas about which series my carb might be?

 

go to a yamaha oem parts site and see what it comes with stock and if its not the same id bring it to a atv shop and ask for the rebuild kit for that carb but dont have them do it they chrage so much... and if they cant figure it out cuz i know around me theres alot of stufff they cant figure out unless theres a book telling them exactly what to do. look on ebay for a new or used one there are some pretty cheap ones

 

check this site out... any part ya need for the carb right there, it doesnt say what model the carb is, but it seems that specific bike only haad one model of carb they used for it. Dillon Brothers' 1986 Yamaha ATV MOTO-4 YFM225S Parts List