Let me preface by saying I've been riding 33 years. I purchased a used 2009 Ultra Classic last year. A Vance & Hines FuelPak, K&N filter, and Vance & Hines Monster Ovals were already on it. I removed the FuelPak and installed a Fuel Moto Micro Tuner about six weeks ago. I'm think about going with a SEST and did an experiment today. I removed the Micro Tuner and plugged in the O2 sensors putting the fuel system back to stock. I took the bike for a ride and it runs good. As a matter of fact, it runs fine. A little bit of "burble" occurs sometimes on deceleration, but other than that I can't tell any difference.

Over the years I've always heard that if you add a high flow air filter and exhaust then you need some sort of tuner. I know all the reasons such as richening the fuel mixture to run cooler etc., but other than that, why is a tuner needed? Please base opinions on if a tuner is needed, not just wanted.

Thanks!!

 

If you get pipes and an air cleaner, you dont need a tuner. The bike's ECM will adjust, it will not burn up from running too lean. In the posts following this, you'll hear all about running cooler, more power, etc.

Personally I think its mostly in the imagination. 99% of the 3-5% gain you get from a stage one comes from the new hardware, not the tuner.

 

I was in a similar situation. 09 FLHR, VH basic slip ons with a Big Sucker AC. Previous owner did no tuner. I have installed a VH Fuelpak. My reasoning, from all I could learn, is that the stock ECM will suitably compensate the fuel mix with a single Stage 1 component installed but as soon as you run both AC and slip ons the risk is that the mix will be too lean. Combined with the fact that these bikes are already EPA lean from the get go that could present a problem. A tuner, in its most basic function, will correct that. Of course it can run well beyond that but that is the very simple entry level purpose. I welcome any correction to this logic.

I myself am actually thinking about putting the stock cans back on to quiet the bike. Keep the Big Sucker. In that I am not sure the Fuelpak would be necessary.

 

This is incorrect. The ECM can adjust to stage 1 hardware. No reports of bikes blowing up.

 

cool. Perhaps I'll pull the Fuelpak out then felt very much the same with and without so part of me is more comfortable without that in the loop. Thanks.

 

You may be comfortable with that.... I am not. The bikes are lean from the factory for emission purposes to start with and more air NEEDS more fuel. Lean is lean.
Why does a good fuel map help even a bone stock bike if the ecm can compensate? Why does HD, and every manufacturer of pipes recommend some form of fuel management if the AC is altered?
Just because the bike "appears" to be alright doesn't mean that that's what's best for it........
But if you want to roll the dice be my guest

 

I agree with you. If you look in the Harley parts catalog you don't need to make any changes to the ECM if you add slip on's. But all the Harley Screamin Eagle AC's say an ECM re calibration is required. The cheapest and easiest way to go is to have your dealer do a stage 1 download. You will still meet the EPA emmisions requirments and the ECM will be able to adjust properly for the increase in air flow. It also raises the Rev limiter to 6200 RPM and has a more aggressive timing curve.

 

I am running RC components slip ons with no baffles and a stock air cleaner and my bike runs fine. No download or fuel pack, I think if I were to put a high flow air cleaner on I may have to alter that to a download.

 

If you feel better without tuner, just pull your spark plugs every once in a while and see what they look like. The plugs tell you a lot about whats going on with your engine.

A few good reads about spark plugs.

http://www.ngk.com.au/spark-plugs/te...-plug-analysis.

http://www.ngksparkplugs.com/tech_su...d.asp?mode=nml

Just an FYI. My buddy ran the heavy breather and true duals on his street glide with the 96cu for about a year without a tune. Ran fine, never had any problems. Pulled his plugs at the end of the year, they were white as a ghost... it was obviously running waaay too lean. Cams and Thundermax were installed over the winter.

 

You can change the mufflers, and even the headers, but add the high flow air cleaner and you're leaning out the air fuel ratio to the point that some kind of tuner becomes required to adjust the air fuel ratio. If not performance will suffer and possible engine damage will occur in the long run. It's the same in modern cars and trucks, they are already tuned from the factory to run lean, you make modifications that will will make them run even leaner, like open exhaust and air cleaners you need to to make changes to the onboard computer so they don't run too lean. The factory ecm is designed to make minor changes, to take into account someone changing one thing or an another, but it is very limited. A tuner will allow you to make all necessary changes to allow the bike to perform at maximum efficiency and power,