the bike just broke 15k with 17/42 gears. I drilled the slide out to 1/8". wasn't really that much bigger than they were. I do change the oil frequently between 500 and 3000 miles depending on what kind of riding. Valves were adjusted 1500 miles ago and weren't that really off. I do all kinds of riding. I don't usually ride over 75mph, I was just passing someone and noticed that my little girl didn't want to go.
PS -I am using the GPS for speed reading, not the IMO. I find that the IMO isn't very accurate regardless of wheel size setting.