Hola, I bought 3 Mikuni mainjets (130, 132.5, 135). I got them from rockymountian atv but they sent OEM jets instead of original ones (the square within square simbol is not carved on the mainjet) which I totally disagree
. I tried first with the 132.5 but I could not ride beyond first shift `cause the engine turned off. Then, I tried 130 and could ride ´til full throttle but only for less than 15 mins ´til the vento started to feel slow with out power, did the plug chop and got a black plug. Then, I tried with a dynojet 136 = mikuni 127 but could not ride beyond 3rd shift. It seems dynojet convertion is not accurate. I will try with a Keihin 140 = mikuni 122.5 which i tried in the past (can get only 80 km/h). I´m not sure what is going on cause I ´m going one step backward (decreasing the size) instead of sticking with the 132.5. I forgot, the muffler was packed with lexx 4T before using the 130. There is no air leakage in the inlet or outlet carb pipe, air filter is clean, compression? I think is good ´cause been riding with the mikuni 120 with excellent results but white plug.