Your chain is probably fine. You need to check the tension on the motor plate once and a while and may need to tighten it periodically (if it's loose enough, you may need to slide the plate away from the axle to tighten it--look at step 4 in the conversion kit installation instructions that I've attached, but envision the wheel still being on the bike--you shouldn't have to take the wheel off if you have a cone wrench the right size). Just be careful not to get the tension too tight since that could damage the motor.

http://www.izipusa.com/img//pdf/6437...7a32e3ed05.pdf

It isn't a big deal to remove the motor drive freewheel or chain. In fact, there's a mod described on ecoforumz.com to bump up the speed of the standard OEM ezip bikes or conversion kits by installing a smaller motor drive freewheel--moving from a 20 tooth to 16 tooth freewheel. Here's a link to the thread on that mod, including information on where you can purchase a left threaded, 11 tooth freewheel. http://www.ecoforumz.com/electric-bi...-oem-pack.html