I had a 1984 V45 Magna, the sister motorcycle to the Sabre line. It was fun to ride- for a short distance. The seat was a torture device, my rear end hurts just thinking about it.
I bought it new and probably put around 25 or 30, 000 miles on it. Overall, the worst bike that I ever had as far as reliability goes. It was affected by the defective camshafts that Honda had back then. A recall was issued by Honda, but I never got the notice even though I was the original owner and my address hadn't changed. I had to deal with it at my own expense 20 years later.
After it was a few years old it would not restart if I filled the gas tank right up. If I filled it to 5/8 or less it was fine. You have no idea how much of a problem that is on a motorcycle that hardly holds any gas to begin with!
I was on a ride with some friends and one of them informed that my forks were really flexing a lot, as though there was something wrong. The next day I took it apart to check it only to find that three of the four down tubes were cracked completely through, and the fourth was cracked half way through. I was really close to having the front end completely fall off at 60 MPH. That was it for that bike, but I have had three Honda V4's since.
I'm sorry to hear this, I haven't heard many problem bikes for some. But as far as the cams, sounds like you had an early Honda symptom known as "chocolate camshaft" this was die to rushing the production of the bike and using poor materials back in the day. It happened with early 83 and 84 models and some into later. Glad you didn't let that be a bad taste in your mouth for the V4. Good to hear you kept riding!!!