Is a 1980 Honda cm400t a good beginner bike? I'm just looking for something that I can learn how to ride and ride in the city?

I have completed the msf course and was looking alt 250's but couldn't find any near me in price range but the Honda 400 was

The 400 would be better than a 250. In the chance you need to maintain highway speed the 250 is too light.

Rode a cm250 22 miles to work for 2 years, bad decision.

My wife's first street bike was CM 400, she liked it for awhile until she learned to ride better than jumped up to a Ducati 626.

Any 40-year-old vehicle will have a problem with the dried-out brittle plastic parts -- including the wire insulation.
A reliable 400cc will get over $1000. If he is asking less, he knows it has problems. For me, a motorcycle is cheap transportation, something for full time riding. For me, an unreliable bike, that will be parked for weeks or more while you try to find obsolete parts, is unacceptable. *IF* you are riding just for fun, being in a cage while waiting for parts is acceptable.

If the reliability is acceptable for YOU, it is a good little bike. It is a middle-weight bike, capable of easy city riding as well being able to cruise coast to coast on the Interstates. My first middle-weight bike was a new '82 Suzuki GS450E -- which took me from Los Angeles to Seattle and back.

That's fine. Good city bike.

Yes, a very good bike for a novice that generates about 43bhp with a top speed of about 100mph. Not too fast, but enough for overtaking and motorway cruising. It's based on the CB400N so engine parts are plentiful.
The rectifier is a weak spot so make sure it's been ungraded.

That would be at the top of the learning curve for a beginner, with a lot of power to handle and quite heavy in the beginning. If you're still shopping for a bike, ask yourself which one you'd like to have to pick up after you knock it off the kickstand accidentally. Now, go test ride a few bikes.

Excellent Choice. You night have electrical intermittents, though, and might need a new fuel tank. This happened to me on my '83 CB650. New reg.rect, too, avoid the Chinese ones.

I had the 82 Honda cm250c the CM is definitely a great beginner bike. 250 or 400. I miss mine. I sold it and regret it.