Motorcycle Forums » Harley Davidson

Okay....Now I'm really confused..!

  • March 17, 2014 12:38 PM PDT
    I bought a 2013 Street Glide finally figured out which pipes to go with (still trying to decide on High Flow A/C)...anyway all you hear about is this tuner that tuner, get a SERT don't get a piggy back unit blah blah blah.....Not wanting to open her up and do cams so I was just going to do a stage one. Hell, now I read that the new EFI units will adjust your AFR (air/fuel ratio) without a tuner. Unless you do a stage 2 or more. Granted, it will still be running a little lean Thanks to the EPA, Does anyone else have any knowledge of this info?? By the way, I got this information from the engineers from S&S cycle. God I miss carbs and gear drives...!

    Trippin my ass off!'

    Thanks for any insight, and please post where your getting your info from.
    • Moderator
    • 16006 posts
    March 17, 2014 11:14 PM PDT
    Yeah...keepin my 04 carb'd King!
  • March 17, 2014 11:21 PM PDT
    power commanders perform well if you dyno after installation
    • 57 posts
    March 17, 2014 11:46 PM PDT
    When I got the2012 Heritage all I got was misinformation from the know it alls,find out who the best techs and tuners are in your area they install them every day they know what works,the softail runs so good Im thinking of doing the new ultra classic too
  • March 18, 2014 12:43 AM PDT
    Ricochet wrote...
    power commanders perform well if you dyno after installation

    Not a fan of piggyback units. Have had several professionals warn me away from those! If a tuner is neccessary than I will go with the SERT. However, my question to everyone is a tuner even neccessary??? With the O2 sensors, they will regulate the EFI to run within a certain band. My understanding now is that with the newer EFI units on the Harleys is that you only need a tuner if you go into the motor and change out cams and top end. The older EFI units and O2 sensors would not regulate the AFR. Besides, a stage one really only gives you more noise at 2-3 thousand dollars..... all you get is 4-8 gain in one can feel that by the seat of their pants. Granted a tuner will and can dial in the AFR with a good dyno so the motor runs a little richer and cooler, but at what cost of milage???

    Need to find an older EVO and just build another bike.
    • 1855 posts
    March 18, 2014 1:03 AM PDT
    I'm confused myself. What do you want out of the Street Glide which is basically a touring bike in the first place? And when you say older EFI, how old are you talking? My 2010 RoadKing EFI and O2 sensor did a fine job of regulating AFR right out of the factory. And where did you come up with that cost? Can't you just do a stage I download anymore on the newer bikes?
  • March 18, 2014 1:08 AM PDT
    If your just changing mufflers, you need not to do anything but put them on. If your opening the air box or changing the head pipes you'll need a download or a tuner. I prefer the head pipes from Vance and Hines (X pipes) and mufflers, when you buy their system, you tell them the yr, mk, model and size of engine, they configure the tuner to go with their pipes and mufflers for your bike. It's all plug and play from there. Works great...
    • 57 posts
    March 18, 2014 1:43 AM PDT
    Like I said misinformation,I was told by many if you change A/c and pipes then you would need tuner and I wasn't willing to trust the H-D service rep for that kind of money.I went with Power Commander V S&S cam Vance & Hines pipes and Ness Big sucker a/c new lifters and parts and gaskets and dyno for just over 2k.The bike runs a lot cooler no temp gauge but noticeably cooler and is getting 3-5 mpg better and after I changed out the baffles on the pipes I wound up with 95hp and 110ft lbs tq and worth every dollar.I felt a lot more confident talking to the guys that install the parts than the one selling them,I understand you want to go down a different road so find a good Tech and pick his brain,they love to talk.
    • 1855 posts
    March 18, 2014 1:56 AM PDT
    So I'm still going to ask, "Why"? When you have a touring bike then "Why"?

    @Coley, I understand all of that. I just don't understand why all the extra with a bike you're touring bike. It's not like you need the torque and HP as if you're going to be a "light to light" rider.

    My Heritage does a fine job with airflow mixture and performance. I average at the very least 40 MPG and higher elevations have seen as much as 60 MPG. So again, I just don't understand "Why".

    Now, when I win the bid on that old shovel head I just may boost it up a bit.
    • 5417 posts
    March 18, 2014 2:41 AM PDT
    I believe you are correct that you do not need a tuner if you are only changing the exhaust and air filter.  I have an 07 that I changed the exhaust and air cleaner and nothing else. Runs just fine.
  • March 18, 2014 3:17 AM PDT
    @Jimmy....have a love affair with Fishtails and the Vance and Hines Fishtails have a nice little bark to them, not as high pitched as the Sampsons. @Hunter....I would love to see the Dyno sheet of your bike with stock cams and stock heads pulling 95 HP. Hell, stock is like 72 on a 103 (I believe). Lucky, I do believe that you are correct sir, but do you think if I changed out the head pipes (still would use O2 sensors on replacements) got rid of the catalitc converter and added the V&H fishtails and a high flow A/C do you think that the O2 sensors would keep it within proper paramiters?

    Thanks all for your replys.... Yeah I know Jimmy, leave it the hell alone and ride it!
    • 57 posts
    March 18, 2014 3:44 AM PDT
    I will have to look around for dyno sheet ,we left heads stock but as i said replaced stock cam with S&Scam think you are right about stock hp let me get back to you we just packed up all of our things and moved it into garage so we can replace all of the flooring in the house, I'm sure i can find it in a day or two
  • March 18, 2014 11:41 AM PDT
    Thats alright Hunter....don't need to see it, you've just explained the HP gain to me when you mentioned cams.
    • 57 posts
    March 19, 2014 1:01 AM PDT
    Trippin, Thanks for letting me off the hook because Im not going to find my service manuals for some time, Let us know what you come up with Tuner or No Tuner for the set-up you have chose,
    • 1 posts
    March 22, 2014 11:13 AM PDT
    I'll try to offer some helpful advice on the subject.

    Changing pipes/ air intake:

    It's all about air flow. If you change just your pipes then no changes to air/fuel are needed because air is still flowing at the same rate. The rate of airflow only changes when the intake is allows the air volume to increase.

    The bikes ability to compensate for changes in the air flow is limited. The bike is designed to adjust air/fuel mix for outside air temp, altitude, air flow, engine temp, etc... but these changes are all based on a stock intake/exhaust. When you change that dynamic without tuning the bike you will cause the engine to run lean.

    HD already sets the bikes to run a little lean in order to help comply with emission requirements so, not adjusting the air/fuel mix to compensate will cause the engine to run very lean. This can effect performance and engine life. When you consider that an air cooled engine requires fuel to act as necessary part of engine cooling, it becomes clear that running overly lean can present issues.

    Aftermarket A/F tuners VS SERT:

    There are advantages and disadvantages to both.

    The SERT is adjusted using HD software so, it must be tuned at a dealer. It can only be assigned to one bike and cannot be reprogrammed for use on another. However, the big advantage to the SERT is that it can do more than just A/F mixture. It can adjust spark timing and allow changes to sensors.

    Aftermarket tuner {Power Commander, etc...} will allow for adjustments in A/F ratio but not much else. Although they can be reused.

    If you are simply changing intake, exhaust and maybe a mild cam adjustment then an aftermarket A/F tuner is a good choice. If you are planning on engine mods or drastic cam changes a SERT is your best bet.


    It is a common belief that carbs do not need to be adjusted for air intake. This is not really true. Although later model carbs can adjust for changes in altitude and minor intake changes fairly well, if you make large volume changes to your airflow you may become dangerously lean. It is important to engine life that engines are not run in an overly lean condition. I personally rejet every card on a bike that has intake modifications.


    Overly lean engines have a tendency to seem as if they are performing better than a suggested A/F will and they do. Racing engines run very lean.


    The important thing to remember is that although short term performance may be improved, the engine life is going to suffer. Race engines run extremely lean because there is another engine available for the next race. They are not meant to last. Don't confuse a lean condition for a good running engine.

    Dyno Tuning:

    If you want to get the most out of your bike have it Dyno tuned. It costs more but is worth it. There is no way to get the best A/F ratio without it. That being said. Power Commander does a pretty good job of providing reference material to get your bike fairly close without a Dyno and the O2 sensor system seems to work pretty well if you spring for it.

  • March 22, 2014 11:47 AM PDT
    STBobber, thank you sir...very will put! I have decided to go ahead with the SERT due to that fact that I would like to (after warranty) slap in Woods 555 cams and adjustable pushrods and have the heads flowed. Still trying to figure out the A/C I want to use(actually like the small round stamped cover from the Moco, kinda looks like the old Bendix covers) and am probably going to go with the 2 into 1 thunderheader....Thanks all for your insight and information. Oh and ST....I found a very good shop in my area for dynos and he can and does tie into and adjust SERTs....