Does anyone know the wiring modification to derestrict the 3TJ CDI ?
There used to be some instructions on the web but the links seem to be dead

Racing or road use ?

Whats the difference? Is road use just getting rid of the speed restrictor, and does race use increase the rev limit?
Also is there any advantage to advancing the ignition?

ADG wrote:Whats the difference? Is road use just getting rid of the speed restrictor, and does race use increase the rev limit?
Also is there any advantage to advancing the ignition?

I think 'derestricting' the cdi increases the rev limit, removes the speed restriction and bypasses the fuel switch and sidestand switch- not ideal for a road bike.

An M-max or POSH box (or gold speedo convertor) is easier if you can find one.

The kph to mph convertor is probably simplest but I dont really fancy the idea of a speedo setup that can read 180kph becoming a 180mph one - so that its only using ~5/8 of its swept area

Besides someone has already put a mph speedo in mine.

Mine has a converter and its fine.
Have a look on your CDI and see if its marked 3TJ (restricted) or 4DX (unrestricted). If its a 3tj then it needs a signal from the speedo at 0mph / kmh otherwise it restricts to 12.5k revs in all gears, mph speedos don't send this signal
If you take off the top fairing there should be some wire that would normally go into the speedo. The easiest way to sort the bike out would be an M-Max box, it plugs into the speedo wires.
After that a 4dx cdi would work.
If you couldnt find those you need a 3tj speedo and plug inthe wires then fit a kmh > mph converter.

So to derestrict a jap spec SP its as simple as plugging In a 4dx cdi or is there more to it?

You can do that - the SP might have a slightly different ignition curve but a 4dx cdi will run it

Drunkn Munky wrote:So to derestrict a jap spec SP its as simple as plugging In a 4dx cdi or is there more to it?

Yep, they swap straight over.

I got hold of a 4DX TCI unit to derestrict mine, when I came to swap the two units over I discovered a little black box that was unplugged from original 3TJ TCI I plugged it back in and this allowed bike to rev past 12500. Would this be an M max box?
Happy Christmas guys and girls