If your other motors are bad here is a "reverse" rotation motor......you need one for your villain as it has counter rotating props The standard motors on an EX are 23T........these are 21T......and the Big trinity's i showed you are 19T:

http://cgi.ebay.com/Traxxas-Titan-55...item3357761b0c

and a standard rotation:

http://cgi.ebay.com/Traxxas-3975-***...item4cebd7a784

Heres a motor chart from kershaw designs............check out the 650's!