This comes up from time to time; 'My fork tubes are bent or rusty, what to do?' Finding a good used set will be the cheapest solution if yours are beyond repair, or you might get very lucky and find some NOS replacements. But new fork tubes are available...
http://www.frankmain.qpg.com/
Call for current prices and availability, and he does offer custom lengths for you 'chopper' fans.
http://www.frankmain.qpg.com/
Call for current prices and availability, and he does offer custom lengths for you 'chopper' fans.