Well today I went to a Rally and had my 13 CVO Road Glide, with Vance & Hines Power Duals with Hi-Out Put mufflers and SERT re dyno tuned, I had Ernest ET Smith form Max Power Mobile Dyno do the Dyno on the bike. He is out of Concord NC and he does a lot of the Harley Dealer’s Dyno’s in the area for them, when folk do major engine builds.
I learned a lot from him today, he let me watch what he was doing and explained in detail what he had done and what the Harley Dealer had done when they dyno’d the bike.
When you have Harley dyno it, they still run the bike to lean that is a major reason for your heat off the motor and your great gas mileage. My graph at the AFR’s from Harley is nice and smooth (SAE 5 Smoothing) When Harley did it they set the AFR mixtures to 14.1, but once you ride it the 02 Sensor kick in and lean it more.
What he did was dyno it at the 13.4 to 13.6 and some places 13.8, and cutting the 02 sensor out of the equation so that the AFR ratio will not change. He told me to ride it for a few tanks of gas and check mileage, he showed me where to change and how much to change if the mileage is under 38 MPG. He did a SAE 3 smoothing which will show up more mechanical, electrical or fuel problems.
It took him a total of about 5 hours doing it, there is a lot of inputs that have to be made, what Harley will do is take a stock program that has already been written and do about an hour or 2 of work to tune it. I am no longer getting the little bit of surge that was happening, now runs smooth of a baby’s bottom.
He did also mention that wider tire you will have less torque on the dyno run, more résistance on the drum.
I have the dyno sheets just need to scan them and load the up, but gained 3 hp to 89 and torque basically stayed the same at 109.