Schwinn Jaguar Cruiser Rear Hub Replacement

I have a 7 speed Schwinn Jaguar Cruiser with an 80cc motor kit installed. I am looking at purchasing the shift kit from Sickbikeparts, but I need to change the rear axle since it is made of the standard steel. Where is the best place to buy a replacement hub or axle for this particular bike. I have searched the Schwinn website and can not find the specs on the bike, so am not sure which hub assembly to purchase. I have been looking at the Shimano XT M775 CenterLock Rear Disc Hub from Outside Outfitters. Has anybody made this mod on this particular bike?

why do you need to change the rear hub for?im sure the stock one is fine.
the engine chain goes to the shiftkit then down to peddals,the peddal chain then goes to the rear wheel and drives the bike threw your bike gears,since its not a direct hookup with your engine to wheel,then there would not be a lot of force on the rear wheel and the standard one will work fine.

One of the requirements that is listed for the kit is a chromoly rear axle. It states that a standard steel axle would bend. It would be easier on wallet if it works with the standard axle, but being a newbie i didn't won't to take the chance.

My stock one works fine so far

Thanks guys for your help!

My rear axle bent after installing the shift kit (cheap dept. store bike). I found a hardened one at a local bicycle shop. He just happened to have a lot of used parts he keeps.

Old Motorbike, were you at speed or just taking off when the axle bent?