Fork Tube Size?

[MoonClipper]

So due to something I won't go into here, I need new fork tubes. Does anyone have the diameter of the tubes? Specifically for the 1982 XS400 Maxim. Not sure if the sizes vary by year. My inner tubes are bent, so ideally I could find just some new inner tubes instead of a full set. I'm finding some used forks for around $100 on ebay, but I would like to see what other options there are before I jump the gun.

Thanks everyone.

 

[tstidham]

According to this page: YAMAHA FORK TUBES BY FRANKS FORKS that model has 35mm forks.