QuestionI am restoring multiple Honda 350fours, but all have the same problem, mid range sputter around 5000 to 6500rpm range,then they power thru. Have used 3 different sets of carbs all rebuilt,one by wire george in TX.The ignition is pointless, valves are adjusted,new plugs,3 different motors. I have vac balanced the carbs.I just can't figure what is up. Can you shed any advice. Thanks Tom
AnswerTom, the bikes were jetted kind of lean from the factory. If you have changed the exhaust or intake systems, the bike should be rejetted, which may include raising the needles, by lowering the clip position on the needle.
Mid-range leanness is generally related to the needle taper/position.
The last few 350-400F bikes I have worked on responded to an increase in the main jet sizes from #75 to either #78 or #80.
Bill Silver
