I 've fitted a dtr 125 engine in to an xvs frame it's 90 % done but I m struggling with some of the wiring an I find the wirng diagram confusing 

This is what I m left with 

Tail light wires 

Black (earth ) yellow ? Blue / red ?

Rear indicators I have 3 wires one black i assume shared earth other 2 are dark green an dark brown which is left an right ?

At the front I have a blue a red / wire labelled parking light there is no side light fitted to this bike can I chop off this wire 

No guarantees as its a mongrel, you will need to connect and see what happens with the tail light, I would expect the yellow to be the brake light personally, on my dt the tail light feed is blue with the earth being black.

As for the indicators brown is right, green is left. Pretty much all yams have it that way.