My RD-350 was a '73 model, first year I think, bought it summer of '76 right out of college. Guy I bought it from was a UPS driver and two years later a co-worker! 6-spd trans, was a fast bike for it's displacement. I had it over 100 indicated MPH a time or two. You had to like to shift a lot though. And some how the baffles for the mufflers got cut off really short. One Sunday afternoon the local Police officers in my home town thought it was making too much noise and pulled me over. I showed them the baffles were in, they looked at me cross-eyed and let me go. It would rattle windows in the down-town business district of my small home town. ;-)
IMO, the '73's were a great looking bike, pic's here,
http://en.wikipedia.org/wiki/Yamaha_RD350
In '74 Yamaha went with day-glo colors, orange, and a sickly green, not near as sharp looking. My Buddy's Dad had a green '74 that only had 1000-2000 miles on it I could have bought cheap 3-4 yrs ago. But pushing it from my Buddy's place to his Dad's place about 2/10ths mile the morning of the auction was enough fun for me, flat tires, dragging frt disk brake... I didn't even get a bidding number.
Yep, back in the 70's Yamaha was pretty bold, going racing against 750 CC bikes with a little 350, the TZ-350.
The RD was a nice street bike for a 2-stroke, had oil injection, no mixing gas/oil, and a quart of oil went a long l-o-n-g way. Most times I got around 35-40 MPG, if I'd have slowed down a little it would have been better, but not near as much fun.
The day some lady pulled right out in front of me while she was leaving the laundromat and I bounced off her left front fender while I had both wheels locked up trying to stop, even had my headlight on... I decided that maybe I'd be better off going back to dirt bikes. Fast forward about 5-6 yrs to 1983 and I found my '73 Ossa, and even though it hadn't run for 3-4 years, I couldn't pass it up for $100. Had it running an hour after I got it home, the replacement Mukuni carb was really dirty, but simple to clean/rebuild.
With today's electronic engine control systems, electronic fuel injection, I can see 2-strokes making a come-back. They may have to put cat's on the street bikes, but I guess they want to put them on weed-wackers too. 70 MPG is pretty impressive!
Ohhh Speaking of impressive, former co-worker would ride his Honda CBX to work on nice Friday afternoons every once in a while, he worked 2nd shift. Talk about a sharp bike... those SIX exhaust pipes just catch you eye!. With a little coaxing I think somebody could have bought that bike, it was really clean and ALL original.