My dt125r will spark at times and then just stop. When it sparks it sparks for a few seconds and then stops. Does anyone know what this could be? cdi, coils etc?

Any help would be good thanks

is the neutral light ok?

yeah mate the neutral lights fine

OK this could be one of several things. Check the ignition and kill switch ciruit is OK with no crud in the switches/damage to the wiring.

next you need a good multimeter and carry out resistance tests of the ignition coil, and the pick ups and coils that supply the CDi.

if all those are within the stated specifacations you are looking at the CDi box itself.