I'd like to get this accomplished without a dealer, but what is the widest rim (front) and tire I can put on a Night Train after removing the fender? Also without modifying anything else involved?

 

On the front or rear? On the front I'm running a 16x3 rim with a 150/60/16 Metz. Plan on upgrading to a 160 Metz next change. You might be able to fit a 180 , but without measuring I couldn't be sure.

 

On the front only. Did you have to have different bearings or anything added?

 

I had to do some work only because I used a rear wheel on the front. Even so, it was only a matter of having about 1/8" milled off the brake side hub, and running a rear brake rotor and hardware. Reused stock spacers and everything lines up great. If you were to get a front wheel that was built for your bike, you shouldn't have any issues at all. Good luck and post up some pics of the new mods!