If your having problems with sliping out of gears and hitting faulse netruals before you run out and buy a new gearbox or engine just try this, i have had success with this on quite a few motors and thought id share it with you,
This is by no means a sure way to fix your problems as you may well have screwed your gearbox but it has worked for me.................
Tools needed:
8mm socket
5mm allen key
Dremel with a smooth grinding stone,
tools will vary between motors to remove your clutch so you will need to check that yourself,
Step one:
Remove the detense arm and spring,
Step two:
Remove Shift star,
Step three:
take your dremel and slowly deepen the pockets in the shift star, try not to make them any wider,
Step four:
Refit and try it out,