On Jap import B4's you will find an extra wire that goes from the gear selector to the cdi with a bullet connector under the seat. This wire is green with a yellow tracer and sends a different resitance for different gears to the cdi. It is used to restrict the B4 to 180kph as set by Jap law. In the first three gears the resistance is 1.5k ohm, neutral is zero and set by the black wire and 4th 5th and 6th 1k ohm. To derestrict the bike we need to tell the cdi that it's always in the low gears and so set at 1.5k ohm. To do this-
You will need one 1.5k ohm resistor, one male bullet connector, one female bullet connector, 6" of 1.5mm electrical wire and one ring end/bolt on type connector.
You crimp one end of the resistor into the male connector and fit this connector into the G/Y wire under the seat from the cdi, then slide the other end of the resistor up inside the female connector so as it acts as a cover/sleeve for the resistor and put the 6" wire coming out of the end of this connector and crimp them together, to the other end of the wire you crimp the ring connector and this is bolted to the frame under the seat. You leave the G/Y wire from the gear selector loose and connect the black up as usual. This will now tell the cdi that it is in the lower gears and the cdi will think that it never gets to 180kph and full power will always be available.
Parts needed.
Resistor crimped in male bullet connector.
Resistor crimped inside female connector with wire out of the otherside.
Finished wire with ring connector fitted.
You can use shrink tube to seal the connectors and give a professional finish.
Pleases note that no animals were in any way harmed or ill used during this operation!