My 2017 Tri Glide is bone stock and runs great and I don't mind the sound of the stock exhaust at all. I do like the cleaner look of the stage 1 AC systems that utilize the stock 107 M8 AC cover. They really clean up the look of the factory air intake by removing the bulky black air box. I chose the SE stage one because it is CARB approved here in California.
With that said the 2017 trikes don't seem to be as lean running as previous years, they seem to be tuned better. I am running a test right now with a stage 1 air cleaner installed only, no tune useing the stock tune and stock mufflers.
To my surprise the trike runs even stronger through the RPM range and did not seem to lean out. The spark plugs look very good. I have run many spark plug cuts (the old fasthion way of checking how rich or lean a motor is running) at all diffrent RPM ranges and diffrent steady cruise speeds this week.
All of these spark plug cuts so far have looked very very good no lean readings at all (all the spark plug cuts looked very much like the plug pics below). Over all this tells me nothing is being hurt and nothing is to lean with this set up. I don't plan on changeing the mufflers which would increase the air flow out of the combustion system.
A muffler change more than likely would for sure start leaning things out more (more air through the combustion system). The bike can only take in and expel so much air with the stock exhaust system. As said my trike runs stronger and shows no signs of leaning out. The factory tune on the ECM looks to be compensating just fine for the AC upgrade only.
In my opinion the 2017 stock Harley fuel injection compensates much better than what folks are being lead to believe. Yes it will control to an EPA tune but that's not going to burn a stock bike up and will still run ok and still get decent fuel mileage. That's what my testing this week has shown me.
I also talked with S&S cycle by phone the other day (was also looking at one of there CARB approved AC units) and they pretty much varified my conclusions here before I started my testing.
They said my 2017 bike will run fine and not burn up with the stock mapping. They said that is what there dyno runs and testing has shown with an AC mod only. They also said if I tune the bike even richer than the EPA map it will even have more gains and if I add mufflers even more gains.(we all know that to be true). They also said the 2017 do very well compared to past years and run well stock.
All this testing has led me to believe the changes below with the stock 2017 tune will work just fine. While maintaining decent fuel mileage. Going to run more test this week and if All looks good I am going to leave the Trike this way as said it runs great.
* Mufflers only stock tune= ok
* Stage 1 AC and stock mufflers =ok
Plug pic in spark plug socket= Front plug.
Plug pic without plug socket= Rear plug.
Ride Safe All,
Bill G