I would say you are being restricted with the air box,I haven't seen one run with less than a #95. Try running the #100 with the filter cover off to get a feel for an open air box. If you are still running black on the plug I'd go back to the br8hs plug. 40 to 1 seems fair to me ran all my dirt bikes there. Go 36 if any doubts. I was able to keep the stock oiler in line seems to be functioning fine. 30 mpg! thought mine was bad think i'm closer to 40 havn't checked in awile,may need to play with that cvt a bit to up your gearing. see what that does for you.
Art-
That sounds like a good idea- I am going to try the air box delete for a short run, with the 100 and check the plug. Maybe a BR8HSplug is OK? Everyone says use the --9-- plug, but what do I know.
I found a K&N filter on their website that has the right size opening to fit the Arreche carb, or so it appears. I might try to get one.
I am currently re thinking the pre mix idea- I just read so much about the possible lean mixture it might provide with the stock pump, so I opted to try pre mixing, but I might hook er back up, and just try an ounce in the tank each fill up for good measure. I am afraid I will forget to carry oil with me and not have it to mix, so maybe the pump isn't such a bad thing after all...
My last fillup last week yielded 51 KM on 1 gallon-=30 MPG.... I thought the stock setup at around 52 MPG was unimpressive. Talk about mileage- buddy rode his Yamaha C3 112 miles last week on a poker run on 1 gallon. Goes 46MPH with only a rear tire and variator change. Not too shabby.....!