Motor dont work but if I change polarity it works in reverse,any ideas

Has the motor speed regulator inside ?
Is there a hole in the motor to adjust speed ?
This kind of motor runs very fast when you reverse them. That's because the regulator isn't working and inverting is like bypassing it
If the motor works in reverse but not in the right connection the speed regulator is blown.
Be carefull inverting the motor can damage the regulator easily. Don't try this with a new one.
Could you put some photo of the motor to see it ? Most decks have generic Mabuchi replacements that works perfect and even better than the original !!!

I checked one of the posts that had about 2 places to get a motor so I ordered 1 from studio sound electronics. Hopefully i got the right one. http://www.studiosoundelectronics.com/cassette.htm I ordered the 9 volt cw

OK got my new motor and put in and works like a charm. Will be putting up some pics of new bbx's