Just picked up a 84 250R for son to play with, ran like crap with 145 main. I had a 137.5 in stock so tried it & bike ran much better only lacks a couple hundred rpms on top. Anybody know what factory main jet would have been in that model year 250R??? Thanks

 

i believe it was a 50 slow jet and 130 main. your elevation could heavily effect your jetting. lean for highier elevation for the lack of air.