Agreed on moving this to other bikes. Also, check out HondaTwins forums. You can find some good forums that are specific to Honda Twins with a Google search.
Those 450s are known for losing tension in the rocker arms with age. Above 8000 rpm you can get valve float that might have caused all the issues you experienced. If you don't buy new rocker arms, then bear in mind that you probably shouldn't rev the snot out of it after you get it rebuilt. You could get new rocker shafts made, but they are pricey.
Good luck.
Camelman