My regret is selling my Suzuki t500r to buy a house back in the 70's. My friend had a kawasaki 500 triple that was fast but mine would out handle it and steady as a rock while his was like a snake. The Suzuki was faster than 750 Norton commando and 650 bonavile, I used to beat them on the road. Later I raced a 350 Yamaha it was air cooled just before they brought out the TZ350. I would beat them off the line and be in the first 3 or 4 into the first Corner then they would come flying past but that air cooled was so reliable and a missile to ride, biggest regret was selling that it would be worth a fortune now. Times change, these days I cant ride but had good times. All were run on Castrol R then and smell was great, it was 16:1 that I do remember. Then they started developing new oils and the rest is history as they say.