Beware of knock off's of Castle Motors

I know Patrick is going to hate this but I hope their rebuild kits fit my 1518, 1520 and 1717. What other choice do I have if I want to keep my motors going??? I am sure they wouldn't be as good as the original (magnet strength and balancing are my main concerns) but since Castle doesn't make repair kits for them then my options are limited. I don't want to support a company that is ripping off Castle but I don't want to bin my Castle motors neither. I must have got a bit of sand in one of my 1518 motors and the rotor wrappings are in pretty poor state. I don't want to run it like this in fear of totally destroying the motor. Maybe a Sirus kit will get it humming again....... Sorry Patrick.