I think you should be looking into a tuner.The HD download only enriches things enough to bring it back to stock AFR values to meet environmental standards.It doesn't get you down anywhere near the 12.5-1 ratio that you need when rolling on the throttle. Contact Dobeck and see what they have for you.
EFI - Electronic Fuel Injection Controllers - ATVs, UTVs, Motorcycles, Snowmobiles, Scooters, Sport Bikes, Watercraft