After all my work and expensive garage time it hasn't worked so now looking at this for a simple almost bolt on option but can't work out how to wire up, my bike only has a power and earth to speedo light not a separate backlight wire. I have an xv125 

 

 

The dark blue wire in your loom is the lighting feed, brown is ignition feed. You should have a red battery positive floating around too.

 

I probably should but don't think I do, the original speedo just had the 2 wires going into it , 

When you say power and earth, are there any other warning lights and such in the xv clock as it may just be the power to light it up.

Nope jusy got a blue wire and a black wire, assumed the blue was the power and black obviously goes to earth,  with the new one could I simply join red and orange wire together and join to blue, so both gps unit and backlight get 12v 

I usually come off of a feed to the brake light switch. if it is less than an amp (1000mA), i come straight off. If more I use a relay. Always works for me.

12 minutes ago, Spike101uk said:

Nope jusy got a blue wire and a black wire, assumed the blue was the power and black obviously goes to earth,  with the new one could I simply join red and orange wire together and join to blue, so both gps unit and backlight get 12v 

Ok, the blue wire IS the feed for the lighting and the backlight. Brown is the ignition feed. If you have running lights it will come on with the ig like main power.

Ok so back to first question,  how can u wire up that speedo

As pinille, pillin, pylinn, previous post said, jump on the brake light feed (basically the ig feed) brown wire. Will only take a tiny amount of juice so no overload worries.

Personally I would go to the headlight, run a wire in nice and tidy. Then make a solid connection in the headlight (ideally soldered) with at least ratchet crimps and then connect the Speedo.