One thing to remember: Bonneville is 4000 feet elevation.
If you're going 'open bike' as you say, It's going to be difficult to do 170mph.
I don't know my land-speed classes, but I'm guessing it's a non-turbo class?
If you can do partial streamlining, like a roadracer, try this:
The front wheel is one of the biggest aero-anchors on a bike,
if you do a dustbin fairing like this Moto Guzzi V-8, you have a good chance.
In the 1950's Guzzi got 190mph out of these bikes with a little over 80hp.
