So I've been working my butt off trying to get this newly acquired bike running for my wife. Currently it will not run, has fuel compression spark, if I disconnect the regulator rectifier the bike starts up and idles, when I reinstall the R/R the bike wont start again. I bought a new oem honda one and same issue. Anyone have any suggestions, I'm thinking maybe stator but it just doesn't make sense to me.

 

The "won't run with the regulator connected" is quite common on 400/450 Foreman models, but it has always been a faulty reg in my experience. Try testing the stator, all three yellow wires should ohm out at the same reading when tested between any two, and not be earthed, but I would buy a cheapo Chinese reg for a 350, and try it, it is just possible Honda have sold you a dud.