what are the requirements for number boards on the front of a machine?

for example:
vintage on a TY175. class-Twinshock B

TB ??

does the background color matter?
white with black digits?
name and state?

if this info is listed in the rulebook please direct me.

quiet crowd...
i guess i'll show up with a white board and electrical tape...

Hi Kieth,
A TY 175 would be a Vintage bike because it's pre 1980. We'd like you to have a B in a large letter on the front and we'd also like to see your name and city/state too.
Sorry about being so slow! I ride slow too.