Cateyes Chain problem and other small mods I have done

Last week I got my cateyes and before starting to ride I took the advice of one of the posts about putting blue RTV on the bolts and tightening everything up. The only part I did not take off was the engine itself... after taking a couple of test rides the chain came off twice and finally the chain came loose the first time and the second time the chain came apart on the connector link and I lost one of the pieces. Also it looks like the back wheel needs straightening which I can do but any tips to do this would help

I found this link on loose chains on another site and I wanted to know if this is right and is there anything else I need to do. Any tips or pointers?

http://www.x-tremescooters.com/techn...justchain.html

Also I want to get a replacement chain since I lost the a piece of the connector link.... I spent about half hour looking for it.... I imagine it would be a good idea to have a spare one anyway.... Are all the chains the same on the Midbikes or are they all completely different sizes. Can anyone point me to a good vendor for one.

Should I replace the sprocket with a better on on the back wheel?

I almost regret getting the Cateyes bike but I enjoy working on it.

Other than the Chain Issues I have done the following:

Adjusted the Carb - engine running alot smoother now

Replaced some of the screws with bolts so I do not have to worry about stripping a phillips screw.

Another slight modification I made was using big rubber washers on the inside of the fairings so they are not touching the metal. I think this will help the vibration problems and cracking.

P.S. I want to thank everyone for their help so far. Thanks PBP!

if the chain keeps coming off, then either

A. the rear tire is not aligned (loosen axle nuts and the adjustement of the chain tension and try to get the rear sprocket straight w/ the front sprocket)

OR

B. the engine is mounted crooked (under the engine mount there is 4 adjustable big nuts and two of them are adjusted by two sets of eye-bolts. try adjusting that to get the front sprocket lined up w/ the rear sprocket)

and about the main connector piece, try finding a bike shop w/ the main connector piece (easily removeable w/o a tool) just bring your chain in and ask the employees if they have any for that size chain.