Is a Dyno tune really worth it?
Road Warrior
Joined: Apr 2011
Posts: 1,596
Likes: 9
From: Cherokee Co. Georgia
Good thread here. Everybody seems to agree that a dyno tune is absolutely necessary. What about running a self tune? TTS, PV, PC and others all have means of properly tuning a fuel inj. HD engine without a dyno being involved. Why not take time to learn the program and tune the bike yourself? Then if not happy how it runs, look for a qualified dyno tuner. Finding someone that truly knows what they are doing is the key I believe. There are several people on this forum and others that are very competent and willing to lend a hand. I am in the same situation right now and would love to see some comparison dyno sheets showing the difference between self tune and dyno tune after they are both done properly. I realize all cells in every table will most likely not be reached or adjusted with absolute certainty without a dyno, but how often are you going to be riding in them cells if you couldn't reach them while doing VE runs?
Cruiser
Joined: Nov 2006
Posts: 241
Likes: 2
From: Bristol TN
I got a PV on my 08 RG and a 103" kit installed in a yard barn by yours truly. Rebuilt my lawn mowers in it and a harley is about the same just a little more simple so I built it there to. Brother has a 12 SG spent around $600 dollars on a dyno and I can pull him anywhere from idle to top end and get better fuel millage than him. His might be a little fat might not be looked good on the dyno sheet. Only God knows where mine is. Is his dyno right might not be is my power vision right I don't think so. You are riding 1690cc if it is a 103" and with a stage 1 you will maybe be in the mid 70's HP and low to mid 90's TQ. You know a 600cc crotch rocket makes 120hp and no torque to speak of but remember it it over 1000cc smaller. If you can find a dyno guy that will give you a smooth power and torque curve and a good AFR in the whole throttle range it want be cheap. Don't just look at the big number look at the curve and the RPM you ride at. I will just leave my PV on my bike and ride it tuned right or not it will never make enough power to suit me but I don't want power or I would have bought a different bike.
Road Warrior
Joined: Nov 2013
Posts: 1,814
Likes: 11
From: USA
ugh because running "good" and running "right" are not the same thing in regard to the health of the engine.
The bike comes from the factory running lean and it runs "good". Do you think if MoCo didn't have to comply with EPA they would push it out the door with the AFR that they do ? If I have a dyno tune done the bike it will run "right", run cooler, and last longer. But if "good" is good enough, who am I question ?
All those guys selling fuel processors are just stealing your money 'cause hey, your bike runs "good" without it, right ?
I just spent $XX on my new bike and I'll be dammed if I'm gonna spend any money to make it run better/healthier......okaaaaay.
Good thread here. Everybody seems to agree that a dyno tune is absolutely necessary. What about running a self tune? TTS, PV, PC and others all have means of properly tuning a fuel inj. HD engine without a dyno being involved. Why not take time to learn the program and tune the bike yourself? Then if not happy how it runs, look for a qualified dyno tuner. Finding someone that truly knows what they are doing is the key I believe. There are several people on this forum and others that are very competent and willing to lend a hand. I am in the same situation right now and would love to see some comparison dyno sheets showing the difference between self tune and dyno tune after they are both done properly. I realize all cells in every table will most likely not be reached or adjusted with absolute certainty without a dyno, but how often are you going to be riding in them cells if you couldn't reach them while doing VE runs?
MODERATOR
Joined: Oct 2007
Posts: 4,108
Likes: 1,964
From: New England
...The program has to put your bike in closed loop throughout the whole MAP (it does this to turn the o2 sensors on) so if you start out with a MAP that is lean your bike will be really lean while you are out riding doing your data collecting. It's very improtant to start out with a good close MAP...
As to the lean comment, I'll respectfully disagree. Most programs use a switching point that is below many of the factory's stock cell figures depending where in the map we are talking.
I think it would better serve everyone if we used leaner and richer as opposed to lean and rich. An AFR of 12.0 is leaner than 11.5 but richer than 12.5 - they are simple relative terms depending on your particular idea of what's lean and what's rich.
There are hundreds-of-thousands of stock Harley's running millions of miles in what some would call a very lean condition. But it's very difficult to find a single incident where those very lean settings caused problems. And if this forum is any example of real life, I'd say we could find a lot more problems being reported due to settings that were simply too rich for the conditions.
Road Master
Joined: May 2008
Posts: 1,196
Likes: 14
From: connecticut
Yes, the program uses a switching point to enable closed-loop operation using the onboard sensors. For those that use an external sniffer, not such a big deal as long as the operator properly calibrates their system before use.
As to the lean comment, I'll respectfully disagree. Most programs use a switching point that is below many of the factory's stock cell figures depending where in the map we are talking.
I think it would better serve everyone if we used leaner and richer as opposed to lean and rich. An AFR of 12.0 is leaner than 11.5 but richer than 12.5 - they are simple relative terms depending on your particular idea of what's lean and what's rich.
There are hundreds-of-thousands of stock Harley's running millions of miles in what some would call a very lean condition. But it's very difficult to find a single incident where those very lean settings caused problems. And if this forum is any example of real life, I'd say we could find a lot more problems being reported due to settings that were simply too rich for the conditions.
As to the lean comment, I'll respectfully disagree. Most programs use a switching point that is below many of the factory's stock cell figures depending where in the map we are talking.
I think it would better serve everyone if we used leaner and richer as opposed to lean and rich. An AFR of 12.0 is leaner than 11.5 but richer than 12.5 - they are simple relative terms depending on your particular idea of what's lean and what's rich.
There are hundreds-of-thousands of stock Harley's running millions of miles in what some would call a very lean condition. But it's very difficult to find a single incident where those very lean settings caused problems. And if this forum is any example of real life, I'd say we could find a lot more problems being reported due to settings that were simply too rich for the conditions.
Yes, the program uses a switching point to enable closed-loop operation using the onboard sensors. For those that use an external sniffer, not such a big deal as long as the operator properly calibrates their system before use.
As to the lean comment, I'll respectfully disagree. Most programs use a switching point that is below many of the factory's stock cell figures depending where in the map we are talking.
I think it would better serve everyone if we used leaner and richer as opposed to lean and rich. An AFR of 12.0 is leaner than 11.5 but richer than 12.5 - they are simple relative terms depending on your particular idea of what's lean and what's rich.
There are hundreds-of-thousands of stock Harley's running millions of miles in what some would call a very lean condition. But it's very difficult to find a single incident where those very lean settings caused problems. And if this forum is any example of real life, I'd say we could find a lot more problems being reported due to settings that were simply too rich for the conditions.
As to the lean comment, I'll respectfully disagree. Most programs use a switching point that is below many of the factory's stock cell figures depending where in the map we are talking.
I think it would better serve everyone if we used leaner and richer as opposed to lean and rich. An AFR of 12.0 is leaner than 11.5 but richer than 12.5 - they are simple relative terms depending on your particular idea of what's lean and what's rich.
There are hundreds-of-thousands of stock Harley's running millions of miles in what some would call a very lean condition. But it's very difficult to find a single incident where those very lean settings caused problems. And if this forum is any example of real life, I'd say we could find a lot more problems being reported due to settings that were simply too rich for the conditions.
on the dyno it's done differnently, first and most important we have the ability to monitor the bike, (temp, air fuel etc.). Secondly most tuners set the target a/f to 13.0:1 and do our data collecting to dial in the VE's Once that's done we can set the target A/F where we want it.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Cruiser
Joined: Nov 2006
Posts: 241
Likes: 2
From: Bristol TN
Run my bike in closed loop in all the cruise range and set the closed loop bias table to look for around 700mv. A narrow band o2 sensor looking for 450mv should be running 14.68 AFR so around 700mv to 720mv it is running around 14.3 to 14.4 in closed loop. Never turned any chrome on the pipes gold or blue. In autotune it locks the whole fuel table to 14.6 because that is what a narrow band o2 sensor can read and adjust the VE table to make it run a 14.6. You don't want to run in the upper load and RPM range at 14.6 it will kill things. The VE numbers in the upper load and rpm range the company who made the map will be close enough not to hurt anything. So if the target AFR is set to 12.0 you might be running a 11.8 to say maybe 12.3 witch will not hurt any thing but might show a little less hp. In the upper end but how much do you ride there. If you want to make sure your high load and rpm VE numbers are correct you can do AT pro and it uses wide band o2 sensors that read a larger range or AFR so it locks the map in AT to like 13.0 and you can run any where you want in the RPM's and corrects all VE number so when you set you target AFR it knows what to do because you VE numbers are correct and if you VE number is right and you ask for a 13.5 in that cell it will be a 13.5.