Tune or Not to Tune - That is the Question
Club Member
Joined: May 2007
Posts: 145,895
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From: 40 miles Northeast of Indy..
Pipes, A/c and tuner of some kind is done by probably 75% or more of us...
she'll run, start, better, cooler, and give a little more TQ and HP..
put in a cam and U'll be amazed at how much more/better she'll run.
she'll run, start, better, cooler, and give a little more TQ and HP..
put in a cam and U'll be amazed at how much more/better she'll run.
Road Warrior
Joined: Aug 2010
Posts: 1,268
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From: Detroit, the asshole of America
Seasoned HDF Member
Joined: Feb 2010
Posts: 5,618
Likes: 5,182
From: Green Country
Here's some interesting information:
"The OEM Harley-Davidson closed loop fuel mixture is 14.6:1. On Twin Cam 96 engines, the closed loop range generally covers under 4000 RPMs and under 40% throttle. This is going to be 95+% of the time an average rider spends on his bike. Even the most aggressive rider would find it hard to spend more than 5% of this time in open loop.
For those of you concerned about open loop fuel mixtures, on TC engines these are set from 13.8 to 12.5:1 depending upon RPM and engine load. So these mixtures are quite adequate for performance work. Riders that are worried that exhaust and air cleaners are going to lean these mixutres out need not worry. Changes in exhaust/air cleaners are only going to change these AFR's by .3-.4 point, yielding 14.2 to 12.9 AFR in a worst case situation. These are still not fuel mixtures that are going to hurt an engine under wide open throttle situations."
I would tend to agree that dyno runs on a stock bike are a waste of time and money, although it would provide a baseline to judge future mods.
"The OEM Harley-Davidson closed loop fuel mixture is 14.6:1. On Twin Cam 96 engines, the closed loop range generally covers under 4000 RPMs and under 40% throttle. This is going to be 95+% of the time an average rider spends on his bike. Even the most aggressive rider would find it hard to spend more than 5% of this time in open loop.
For those of you concerned about open loop fuel mixtures, on TC engines these are set from 13.8 to 12.5:1 depending upon RPM and engine load. So these mixtures are quite adequate for performance work. Riders that are worried that exhaust and air cleaners are going to lean these mixutres out need not worry. Changes in exhaust/air cleaners are only going to change these AFR's by .3-.4 point, yielding 14.2 to 12.9 AFR in a worst case situation. These are still not fuel mixtures that are going to hurt an engine under wide open throttle situations."
I would tend to agree that dyno runs on a stock bike are a waste of time and money, although it would provide a baseline to judge future mods.
Seasoned HDF Member
Joined: Nov 2010
Posts: 17,548
Likes: 7,164
From: Oxford, Nc
Here's some interesting information:
"The OEM Harley-Davidson closed loop fuel mixture is 14.6:1. On Twin Cam 96 engines, the closed loop range generally covers under 4000 RPMs and under 40% throttle. This is going to be 95+% of the time an average rider spends on his bike. Even the most aggressive rider would find it hard to spend more than 5% of this time in open loop.
For those of you concerned about open loop fuel mixtures, on TC engines these are set from 13.8 to 12.5:1 depending upon RPM and engine load. So these mixtures are quite adequate for performance work. Riders that are worried that exhaust and air cleaners are going to lean these mixutres out need not worry. Changes in exhaust/air cleaners are only going to change these AFR's by .3-.4 point, yielding 14.2 to 12.9 AFR in a worst case situation. These are still not fuel mixtures that are going to hurt an engine under wide open throttle situations."
I would tend to agree that dyno runs on a stock bike are a waste of time and money, although it would provide a baseline to judge future mods.
"The OEM Harley-Davidson closed loop fuel mixture is 14.6:1. On Twin Cam 96 engines, the closed loop range generally covers under 4000 RPMs and under 40% throttle. This is going to be 95+% of the time an average rider spends on his bike. Even the most aggressive rider would find it hard to spend more than 5% of this time in open loop.
For those of you concerned about open loop fuel mixtures, on TC engines these are set from 13.8 to 12.5:1 depending upon RPM and engine load. So these mixtures are quite adequate for performance work. Riders that are worried that exhaust and air cleaners are going to lean these mixutres out need not worry. Changes in exhaust/air cleaners are only going to change these AFR's by .3-.4 point, yielding 14.2 to 12.9 AFR in a worst case situation. These are still not fuel mixtures that are going to hurt an engine under wide open throttle situations."
I would tend to agree that dyno runs on a stock bike are a waste of time and money, although it would provide a baseline to judge future mods.
That's good info, Thanks. The ' 08 SE Ultra ( no cat) at our
shop did run 16 to 1 out of the box, but we suspected something was wrong which is why we checked it. We hoped it was a fluke, and not a common thing.
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