As a rule, no, you don't have to tune. That said, you may see some performance changes or faults depending on what you choose. You may not have to tune, but you might have to make some adjustments.

 

Like you, I am a relaxed cruiser; I will never perform the Stage 2 or higher upgrades. But the Stage 1 upgrade isn't really a performance upgrade; it just compensates for the adverse effects of the lousy agreement Harley signed with the EPA a few years ago. The factory setup and tune of the M8 engine are very lean and the air flow to the engine is limited. Therefore, many, if not most, M8 owners have the Stage 1 upgrade done to improve air and fuel flow to the engine to lower operating temperature and smooth throttle response. Plus, you will not get the full effect of sound improvements unless you also install a higher flow air cleaner and have a new tune.

The cost of the Stage 1 can be kept reasonable if you
1. Shop your slip-ons on-line
2. Only buy the basic HD Stage 1 high flow air cleaner (the higher flow air cleaners are over-kill for a Stage 1) and get any any discounts your dealer offers
3, Install the new air cleaner and slip-ons yourself (easy to do with basic tools, careful reading of instructions and patience) and only have the dealer do a basic new tune on the engine. My total cost was just over $1k, including buying the Harley tuner for the dealer to do the new tune.

 

You do not have to flash or tune the bike after slip ons. The intake is hi-flow and even if you went with full pipes, you do not need to change these for a full stage 1.

I went to slip ons only for a little more sound. Every other change was cosmetic..

 

I don't believe the dealer can tune the new 21's properly yet outside of their exhaust. The canbus has changed, and though they have the street tuner, an autotune is usually done with full exhaust that removes the cats. As we know, the cats are in our mufflers. The dealers still don't have the autotune to fit the new canbus to my knowledge. That all being said, my dealer said they usually don't tune for slip-ons only.

 

yes you need to tune for a stage 1 ,
which is exhaust, high flow filter, and the tune ,

 

The HD on-line parts page shows that a Screamin" Eagle Pro Street Tuner (Part Number: 41000008C) is now available for the 2021 Street Glide. Check with your dealer for verification.

 

Yes - you need a tune for a stage 1 - I didnt say it was unneeded BUT you do not need a tune for slip ons as I stated. The factory intake is high flow so in this case if you change to full pipes, that will constitute a stage 1 where a tune is needed. We're saying the same thing... I could see where I was not clear in my orig post..

 

unless you have a 114 ,, you will need to to change to high flow filter ..

 

Hello KissMyDrums,

The S&S slip-ons are 50 state compliant.

Since I live in California, (it has very restrictive laws) the S&S slip-ons were purchased and installed through my local dealer. It does not void my warranty.

I did opt for a stage 2, torque set up.

Thank you for your time,
Lboy06.

 

Correct! I keep forgetting not everyone has my bike.