Recently tried to replace the gas cap on my Max II with a cap that has a built in gauge. I bought it from Route6x6 because it specifically said it would work on ALL Max II machines that have a "screw on" cap which is exactly what I have. That and I'll be honest I was too lazy to get up and measure the existing cap which would've enabled me to shop around a bit. So, the new cap arrived and when I tried it it bottomed out and wouldn't even start to thread on. Returned the cap to Route6x6 and they said that they tried it on 3 different Max IIs and it fit like it should. My question is this, did RI use the same size gas tanks in all their models? Was there a design or spec change at some point? Trying to figure out how my ( as far as I know) factory installed gas tank is smaller than what it should be. It appears to be factory with no obvious alterations to it or the bracket but I could be wrong. Were there aftermarket tanks sold that were very similar in design but not exactly the same dimensionally? Again, just trying to figure out this mystery. Thanks Cup