The aluminum tanks I've experience with dont use the single backbone frame like on qrs. the hot water/air pressure maybe the only option. Unless you have fabrication skills.

Trx250r 6 gal tank, older style 5.2 gal tank in the flyer





The Zilla in my avatar uses the banshee tank with the C&J Roll frame



No aftermarket options for the lt500 250 that I know of

This flyer is way old like from 1989... So the phone # probably won't work!