I was working at a local Honda dealer in 1977, and we took a '73 in on trade. It had over 21,000 miles on it (I kid you not). It was a low serial # (342) and the guy had never ridden it in the dirt; it was his commuter, and he'd ridden it all over the western US. Engine had never been touched.
I traded straight across for a '70 CB175. I put on Petty fenders (IT on the rear), Cheng Shin knobbies, and a Super Trapp on the stock header pipe. It was gutless. Working in a shop has its advantages (cost + 10%), so I decided to do the Powroll thing. Hal Kenyon, the owner of the shop, who had built some killet XL412s, said to do it all, so I did. Bore and stroke (267cc total), big carb, cam, pipe, and ported head. When we pulled the engine apart, it was pristine inside - it even still had cross hatches in the cylinder! What's that saying - no power, no wear?
It was like night and day. Stock, I had to tug on the bars in first gear to get the front end up. Pumped, I could just roll it on in 1st, 2nd, or 3rd. I used to love riding it through all 5 gears on the back wheel. Wonderful engine, never ran hot or gave me any grief. The chassis, on the other hand, was mediocre at best. Built for a small rider (I was/am 6'2"), it had 33mm fork legs which were way flexy. On the plus side, it was fun on the fire roads. And it didn't weigh a ton, either.