Hello guys, new to the CBR400 and I've been having a read on derestricting them. I have a 1988 J model. I've seen the resistor Mod but that doesn't seem to work on the older J model or so I've read? From my own research most people recommend using a gold labeled CDI which is standard on a J model. Does this mean the J is factory non restricted or am I mistaken. If I'm wrong can some one please inform me of how I go about derestricting my CBR. MPH converter? Modify clocks etc etc

Yes J model should have a gold label CDI and won’t be restricted.