Touring Models Road King, Road King Custom, Road King Classic, Road Glide, Street Glide, Electra Glide, Electra Glide Classic, and Electra Glide Ultra Classic bikes.
Sponsored by:
Sponsored by:

Here we go. Asking a newb question exhaust. Stock ac no tune m8

Thread Tools
 
Search this Thread
 
Old Feb 21, 2020 | 12:56 AM
  #1  
gartec81's Avatar
gartec81
Thread Starter
|
Grand HDF Member
15 Year Member
Liked
Loved
Community Favorite
Joined: May 2010
Posts: 4,356
Likes: 887
From: san diego
Default Here we go. Asking a newb question exhaust. Stock ac no tune m8

Well. Got hooked up with a cheap *** danmoto 2 into 1. I have a 2017 m8 road glide.

I have not purchased a intake nor had my old powervision relicensed to this bike.


anyone know if the new m8s are ok if you just run a full exhaust and leave the factory intake with no tune

I know prebious models you could do either intake or full exhaust with no tune. But you couldnt do both intake and exhaust without tuning your bike.

basically i wanna bolt this pipe up and run it for a bit with stock a/c and stock tune.

Is that ok? I have no idea about these m8 motors

 
Reply
Old Feb 21, 2020 | 06:51 AM
  #2  
Hawg Runner's Avatar
Hawg Runner
Road Master
Joined: Dec 2018
Posts: 1,045
Likes: 390
From: Florida
Default

I don't want to steer you in the wrong direction, but I would say it's ok. You can always give Fuel Moto a call and ask them to be sure.
 
Reply
Old Feb 21, 2020 | 07:53 AM
  #3  
EdwardK's Avatar
EdwardK
Road Warrior
Joined: Nov 2007
Posts: 1,800
Likes: 307
From: Houston, Texas
Default

I doubt you will hurt the engine in anyway and it may or may not effect performance. My concern would be the pipes. I have had a lean tune turn a major brand name muffler blue and we all know factory tunes are very lean.
 
Reply
Old Feb 21, 2020 | 09:19 AM
  #4  
RAVAGE88's Avatar
RAVAGE88
Intermediate
Joined: Feb 2020
Posts: 48
Likes: 30
From: CT
Default

With closed loop ESPFI and riding around mostly within a quarter throttle condition with NB O2, it won’t hurt anything at all. I tested this with my own bike (‘19 EGS) and the performance difference without retuning was substantial. Looking at the AFR and other charts, there’s plenty of range within the factory tune to accommodate uncorking the intake and exhaust.

I didn’t retune until I changed the factory headpipes but I’m still running the factory NB O2. I was thinking I’d re-cam but I have gobs of low end torque the way I’m set up now, but I will be going WB O2 with the Auto Tuner pretty soon because I’ll be 10,000 feet higher in the Summer.

MB
 
Reply
Old Feb 21, 2020 | 09:40 AM
  #5  
Puglia10's Avatar
Puglia10
Road Warrior
Joined: Sep 2012
Posts: 1,253
Likes: 482
From: MA
Default

I'm no expert but everything I've read says you'll be way too lean. They're arguably too lean right from the factory, so a pipe will only make it worse. I personally wouldn't run it without a tune, but that's just me. Enter at your own risk.
 
Reply
Old Feb 21, 2020 | 09:48 AM
  #6  
RAVAGE88's Avatar
RAVAGE88
Intermediate
Joined: Feb 2020
Posts: 48
Likes: 30
From: CT
Default

Originally Posted by Puglia10
I'm no expert but everything I've read says you'll be way too lean. They're arguably too lean right from the factory, so a pipe will only make it worse. I personally wouldn't run it without a tune, but that's just me. Enter at your own risk.
Actually, comparing the Air/Fuel Ratio (AFR) charts for the actual tunes, they’re not “too lean” from the factory. There are times the ECM will command a lean or rich condition, but it’s based on numerous variables but never during a cruise condition. And again, I’ve tested this myself and compared the numbers. Additionally, without changing the air cleaner, you’re not allowing any more air into the engine than what was allowed prior to changing the exhaust, so the tune doesn’t need to change.

MB
 

Last edited by RAVAGE88; Feb 21, 2020 at 12:38 PM.
Reply
Old Feb 21, 2020 | 01:39 PM
  #7  
gartec81's Avatar
gartec81
Thread Starter
|
Grand HDF Member
15 Year Member
Liked
Loved
Community Favorite
Joined: May 2010
Posts: 4,356
Likes: 887
From: san diego
Default

Originally Posted by RAVAGE88
Actually, comparing the Air/Fuel Ratio (AFR) charts for the actual tunes, they’re not “too lean” from the factory. There are times the ECM will command a lean or rich condition, but it’s based on numerous variables but never during a cruise condition. And again, I’ve tested this myself and compared the numbers. Additionally, without changing the air cleaner, you’re not allowing any more air into the engine than what was allowed prior to changing the exhaust, so the tune doesn’t need to change.

MB

I also was seeing reports tgat the m8 is not lean from the factory.
 
Reply
Old Feb 21, 2020 | 03:11 PM
  #8  
Puglia10's Avatar
Puglia10
Road Warrior
Joined: Sep 2012
Posts: 1,253
Likes: 482
From: MA
Default

Hm, interesting. I dont know enough to argue lol, but some really reputable tuners on the M8 facebook group have said they've dyno'd them and theyre very lean from the factory. I would tend to believe that considering all the EPA emissions stuff.
My stock bike/pipe gets hot as hell which also tells me its lean, but I've also never had a bike with a cat before.
I am personally waiting to do tune, AC, and pipe all at once, but maybe I'm just paranoid.

If not lean, I would think it'd run poorly? My 08 did just from switching to duals to 2-1 without a tune.
If you do go forward, come back with your results, now I'm curious!
 
Reply
HD Forum Stories

The Best of Harley-Davidson for Lifelong Riders

story-0

7 Surprising Harley-Davidson Products that Are Not Motorcycles

 Verdad Gallardo
story-1

8 Best Harley-Davidson Motorcycles Ever

 Pouria Savadkouei
story-2

10 Worst Harley-Davidson Motorcycles Ever

 Pouria Savadkouei
story-3

Killer Custom's Jail Break Is The Breakout That Refused to Blend In

 Verdad Gallardo
story-4

Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?

 Verdad Gallardo
story-5

Harley-Davidson Reveals Super Cool Cafe Racer Concept

 Verdad Gallardo
story-6

Engraved Rebellion: Inside Bundnerbike's Glam Rock II

 Verdad Gallardo
story-7

10 Motorcycles You Should Never Buy

 Joe Kucinski
story-8

10 Things Harley-Davidson Needs to Fix in 2026

 Verdad Gallardo
story-9

Southpaw Super Glide: A Left-Hand-Drive 1979 Harley FXE Built to Fit the Rider

 Verdad Gallardo
Old Feb 21, 2020 | 06:09 PM
  #9  
RAVAGE88's Avatar
RAVAGE88
Intermediate
Joined: Feb 2020
Posts: 48
Likes: 30
From: CT
Default

Originally Posted by Puglia10
Hm, interesting. I dont know enough to argue lol, but some really reputable tuners on the M8 facebook group have said they've dyno'd them and theyre very lean from the factory. I would tend to believe that considering all the EPA emissions stuff.
My stock bike/pipe gets hot as hell which also tells me its lean, but I've also never had a bike with a cat before.
I am personally waiting to do tune, AC, and pipe all at once, but maybe I'm just paranoid.

If not lean, I would think it'd run poorly? My 08 did just from switching to duals to 2-1 without a tune.
If you do go forward, come back with your results, now I'm curious!
Gotcha, haven't seen any of that but will take a look to see if I can draw a reference. Basing my comments on the many bikes I've built along with the tuning and testing I've done on the TC and M8.

MB
 
Reply
Old Feb 21, 2020 | 09:07 PM
  #10  
gartec81's Avatar
gartec81
Thread Starter
|
Grand HDF Member
15 Year Member
Liked
Loved
Community Favorite
Joined: May 2010
Posts: 4,356
Likes: 887
From: san diego
Default

Even though the 5 year old in me wants to bolt up the pipe and run it..... i should get an intake and tune. Prob will just do tune and then once i sell myself on the corner pick up an intake.

Lol.

Thanks for the info guys. Appreciate the responces
 
Reply



All times are GMT -5. The time now is 03:40 PM.

story-0
7 Surprising Harley-Davidson Products that Are Not Motorcycles

Slideshow: The bar-and-shield logo shows up on far more than motorcycles, some of the company's most unexpected products have nothing to do with riding.

By Verdad Gallardo | 2026-04-29 16:50:35


VIEW MORE
story-1
8 Best Harley-Davidson Motorcycles Ever

Slideshow: Not every Harley gets it right, but these are the ones that genuinely earned their reputation.

By Pouria Savadkouei | 2026-04-15 14:23:21


VIEW MORE
story-2
10 Worst Harley-Davidson Motorcycles Ever

Slideshow: From the troubled AMF years to modern misfires, these bikes earned reputations for reliability issues, questionable engineering, or disappointing performance.

By Pouria Savadkouei | 2026-04-01 20:01:09


VIEW MORE
story-3
Killer Custom's Jail Break Is The Breakout That Refused to Blend In

Slideshow: Killer Custom's "Jail Breaker" build focuses more on stance and visual aggression than mechanical overhaul.

By Verdad Gallardo | 2026-03-18 19:20:32


VIEW MORE
story-4
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?

Slideshow: The Swiss custom shop has taken a Harley Softail and stretched it into something so long and low that it looks closer to a rolling sculpture than a conventional motorcycle.

By Verdad Gallardo | 2026-03-07 16:15:30


VIEW MORE
story-5
Harley-Davidson Reveals Super Cool Cafe Racer Concept

Slideshow: Harley-Davidson's new RMCR concept revives the café racer formula with modern hardware-and it may be exactly the reset the company needs.

By Verdad Gallardo | 2026-03-04 12:23:37


VIEW MORE
story-6
Engraved Rebellion: Inside Bundnerbike's Glam Rock II

Slideshow: A standard cruiser becomes an intricate metal canvas in the hands of a Swiss custom house known for pushing Harley-Davidson platforms far beyond their factory brief.

By Verdad Gallardo | 2026-02-24 18:19:44


VIEW MORE
story-7
10 Motorcycles You Should Never Buy

Slideshow: There is no shortage of great motorcycles to buy, but we would avoid these ten.

By Joe Kucinski | 2026-02-19 14:50:51


VIEW MORE
story-8
10 Things Harley-Davidson Needs to Fix in 2026

Slideshow: Harley-Davidson's challenges aren't abstract; they show up in dropping shipments, shrinking dealer traffic, and strategic decisions that aren't yet translating into growth.

By Verdad Gallardo | 2026-01-13 18:33:17


VIEW MORE
story-9
Southpaw Super Glide: A Left-Hand-Drive 1979 Harley FXE Built to Fit the Rider

Slideshow: Graeme Billington's left-hand-drive Shovelhead is as much about problem-solving as it is about classic Harley form.

By Verdad Gallardo | 2025-12-30 11:27:08


VIEW MORE