i have used a 250 fzr motor in my homebuilt honda 162 replica.not using airbox,it was runnig fine on four bellmouths with filter pads inside. now i have fitted the open megga exhausts it starts and ticks over but is very iffy on pickup.any suggestions on main jet sizes/mods would be most welcome.i cannot afford rolling road/dyno jetting,so any tips would be most welcome.regards colin