Since I got my Ryker last February the mileage has been all over the place. When I put in new plugs (oem) and gapped them at .029 I noticed a little more power as I left my driveway. I have done my own tunes for around 50 years, I never expect any improvement just to keep the norm. So i was very surprised to see better mileage. At a least 5 fill ups I have been getting from 40 to 42 mpg. I have on occasion got that before, but the next fill up might be 31 mph. The original plugs I pulled were gapped at .032. I always make sure the gas tank is full when I gas up. I am hesitant to make any claims, but I have put a few hundred miles on the new plugs and have never seen lower mph than 40 mpg. I don't use any particular brand of gas, I just use what ever is convenient. I have always thought my Ryker got poor gas mileage until now. I would be curious if anyone else can get the same results. I am over 12,000 miles and the "transmission needs service" light has been on for a few weeks, it would be nice to able to turn it off as I am not planing on changing the belt at least until next summer. I can ride year around here as long as it's not raining and not below about 45 degrees.