I have just over 1000 miles on my D8 now. It didn't run correctly from the day I picked it up and finally I got a Test flash which helped a lot. With the test flash my mid range power was much better and Im sure that was do in part to the fact that it had no power between 7100rpms and 7600rpms prior to this flash. I didn’t notice to much improvement in the top end but I don’t spend much time there. My milage is respectable and better than all my other sled except maybe the 99 700 rmk I had (one of the best running sleds I every setup, consistently got over 10mpg). Before the test flash it was about like my modified 03 vertical escapeon milage and after the flash I have seen over 10.5mpg on a nice family ride and nothing under 8.8 mpg on some of the hardest riding I have done. I would have gotten closer to 7 mpg on my old sleds riding in this same manor. So that’s about 20 percent better fuel milage than the old 800 engine, No complaints here.
Oil--I have used only about 4.5 quarts of oil to go 1045 miles. At 9.5 mpg that a 98:1 ratio. It seems like I am using no oil at all in this sled compared to all the other sleds I have owned, but maybe 100:1 average is reasonable in these new sleds. I have mentioned to my service manager that I am using very little oil and he said that the way they are set up to run and it scares him also. A Skidoo riding friend of mine is telling me the sled his wifle is buying for next yr. (skidoo 600) is claming that you can ride for a full season with out having to add oil, so this seems to be an industry direction.
Back to the motor. I still had a minor bog after the test flash that wasn't resolved so my dealer flashed my sled with the lastest production flash. I haven't had much riding time with this new flash to determine if it removed the minor bog or to determine how i feel it performs but my first thoughts are that it may be a bit lean right off idle, resulting in a little performance loss in the low 6000 rmp range, but I only have bout 75 miles on this flash and I haven't developed a good feel for it.
Over all I like the feel of the motor. I think it still needs a little tuning and I hope Polaris continues to work on the fuel/timing map for this motor to give it a more consistent power curve. It seems very strong at time and then it is off a little,--- clutching? But I truly think if a person had a number of dyno runs on this motor you would see a number of dips and the curve would not be as smooth as the carbureted sleds of the past. Just a little more work is needed. It's these little deviations and clutching that makes two very similar sleds with similar HP numbers perform way different in the field.
I like it and think it will prove to be a good engine.