honda a shocking for old parts
they stop makeing parts after 20 years, so anything before 1991 u cant find new parts for
A lot of manufactures do that with all types of products, not just Honda. Once their original supply of spare parts are sold off, sometimes there's not enough demand to warrant
(make a profit) tooling up for a whole another batch.
There's also just so many older Honda products out there still in use that the available parts supplies probably tended to get sold off faster than comparable Kawasaki, Yamaha or Suzuki parts for instance.
And then, the
'bean-counters' at lots of companies like Honda also figure if they stop producing repair parts, some of their loyal customers will just buy a brand new Honda instead of trying to fix the old one... so, its all about max-profit.
Honda has also had so many other manufacturers rip off their engine designs with clones, they probably figure lots of customers will just purchase the lower priced cloned-parts
(for repairing genuine Honda's) whenever possible too.