I have a yamaha yz125 94 i have a problem with the timing there is a good spark i have tryed turning the inside stator but isnt getting the spark at the right time i have redone piston, mains because it isnt timing up right it is also blowing the seal behind the flywheel and petrol is coming out i have tred a all the electrics of a 99 model to no avail it also kicks back when kicking over help

The Stator doesn't give your bike spark. It generates the A/C voltage that the R/R turns into DC voltage. Your issue is with your CDI and or pick-ups Check them for clearence and make sure your ecu is plugged in good.

Fix your wiring or it will not have spark

double check that the motor ground is good,
that the kill switch is working proper.
neutral safety switch,
i have seen the magnets get damaged from rough play and not do there job also

Test the stator those go in them quite a bit

Yes, there should be oil inside the stator cover. Try a new spark plug.

This is the order in which you should check the following

1. Check fuses(If all are good,Continue down the list)
2. Check for power from the stator while turning the engine over(If you have power continue down the list)
3. Check coil (Check voltage input while turning engine over)(if no voltage continue down the list)
4. Check CDI (The only way to test is to try on another atv of the same year and model)

Please take time to rate this fixya

If you are getting a nice bright blue spark then no, the last time I had a problem like this it was sugar in my tank. If you taste a bit off your finger and it is the slightest bit sweet, then some one has sugared your tank. If so just flush the tank with a little fresh fuel and then flush the carb, and fuel lines by spinning the engine over for a bit then try to start again.
Is yours an electronic ignition or points. If points gap could be wrong or even timing slipped. That has happened to me also.