Years back Hodaka importer Pabatco used to produce a neat little hop up guide for the bikes with descriptions of flat track, road race, and various other weird conversions for the bikes. If anyone still has one they'd like to get rid of let me know. Money or trades will work.
Rick had a DIRT BIKE magazine Hodaka project bike for sale on eBay a while back (it didn't sell). Maybe if you email him and ask about that bike you could mention the manual that you seek. He might just sell it to you. Does he know you?
I met him about 20 years ago at an industry trade show when Eric Gorr and I were working with my old buddy Vic (Mr.Know It All) Krause. Rick and Eric are friends so I may take the route that you've suggested. Thanks!
I've been told that a guy named Harry Taylor did a lot of R&D for Hodaka and is still involved in the vintage scene. His number is 541 566 3470. He might be a good place to start.
Did you find what you are looking for yet? I'm pretty sure that I'm going to the Hodaka reunion in Athena, OR coming up next month. If you want me to, I'll look around for the guide.