It would seem to me that someone could make a guage. The problem I think with incorporating one into the gas cap would be that the cork slider cant get to the bottom of the tank like on a lawn mower because the center frame is in the way. I would think that if someone drilled into the tank and put a couple of 90 degree elbows, on on the top, and one on the bottom, and put clear tubing between them - that should work. But it might look like a hack job unless the tubing and elbows where nice - just a thought.

When I had my YZ, I would just use the odometer to estimate how much gas I had. You can get one from several places, or just get a GPS with one built in.

 

i bought the ron wood tach,it broke a cpl months ago.the arm is sitting in the bottom of the tach.

 

Unless you isolate the vibration of the frame from the dash, the needle on the tach will do that - Both the Ron Wood Racing tach and the Bombardier tach is made by the same company.