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If i know a good place that dyno's a bunch of Harley's, do you think they can do my Victory as well? Is there anything special that needs to be done with the Vics or can any authorized DynoJet tuner work?
 

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If i know a good place that dyno's a bunch of Harley's, do you think they can do my Victory as well? Is there anything special that needs to be done with the Vics or can any authorized DynoJet tuner work?
The place that did my Vegas, ..Powerhouse at Nerang, authorised Dynojet operator, tunes a wide variety of street and race bikes including HD.
Steve did a good thorough job on my Victory and any followup tunes should I add cams etc can be done for a lazy $50!
An engine is a basic air pump with fuel injected into it.
Lit up by a spark plug.
Granted someone who only tunes Vics all day long would have a bit more knowledge as to the likes and dislikes of a particular brand of engine.
Id be interested to read more replies to this topic actually.
 

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We have a local shop that is run by a guy who does 95% HD stuff, from routine maintenance to major builds / rebuilds. He'll Dyno any bike you give to him and he gets very good results.
The Dyno don't care what badge is on the tank and neither should the guy running it.
 

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We have a local shop that is run by a guy who does 95% HD stuff, from routine maintenance to major builds / rebuilds. He'll Dyno any bike you give to him and he gets very good results.
The Dyno don't care what badge is on the tank and neither should the guy running it.
Perfect answer right there.
 

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Please help cure my ignorance. I understand what a dyno (dynomometer) is. It is a device that holds a bike in position with the rear wheel on roller(s) and measures various aspects of performance - primarily torque and horsepower. During the dyno run, the bike is run through all the gears at various rpm. The outpout is a straight forward curve of HP/torque vs. rpm (or maybe speed). This would be a simple dyno run. Now we get to the part I don't understand well. What is a "dyno tune". More specifically:

1) What instrumentation, if any, is attached to the bike? For example, is the exhaust analyzed chemically to determine air/fuel ratio? Is the fuel flow measured? Is something else measured?

2) What changes are made to the bike and what is adjusted during/between dyno runs to accomplish the "dyno tune"?

3) Wouldn't the changes made to one brand of bike likely be different than the changes made to another brand? For example, if you were dyno tuning a Valkyrie, you would need to know how to adjust and synchronize the six carbs. If you were dyno tuning my 2006 HD softail you would need to know how to manipulate the fuel injection (probably by the addition of an aftermarket fuel controller). If you were dyno tuning a vic, you would have to deal with a different fuel controller and the O2 sensors.

4) Do dyno tuning experts know all/most of these various tuning methods or do they specialize in one brand?

Thanks for any light you can shed on my ignorance.

G'day,

Vinish
 

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Someone will be along to explain in much more/better detail, but in general...

The bike being tuned will have some sort of fuel controller on it; Power Commander or one of the various others. With all controllers they will be able to adjust the A/F ratio to be the best it can be at any given throttle position. With some units they can also adjust the timing for better results.
 

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1) What instrumentation, if any, is attached to the bike? For example, is the exhaust analyzed chemically to determine air/fuel ratio? Is the fuel flow measured? Is something else measured?
You only need two inputs. A tach signal for rpm and either 1) a tube inserted into the exhaust pipe, or 2) wide-band O2 sensors screwed into bungs in the head pipes.

2) What changes are made to the bike and what is adjusted during/between dyno runs to accomplish the "dyno tune"?
The only way to tune is to have a means to make changes to the fueling. I will do this assuming there is a Power Commander fuel controller on the bike, since this method is the most common over all brands of motorcycle and the most involved.

You warm up the bike and re-set the throttle points/tps for zero throttle and 100% throttle.
You will tune the front cylinder 1st.
You run the bike at idle and set the desired air-to fuel ratio at the rpm range where the bike will normally idle.
You put the bike in 4th or 5th gear and do a dyno pull at 2% throttle position and save it. The dyno will show a graph through the rpms from the lowest to the highest it revs at that position.

The dyno software will show an air-fuel graph at the bottom like this (The dashed line across the graph can be set to the desired ratio by the operator):




The Power Commander software has a fuel table like this:


Now... the operator will adjust the cells at each rpm, over several sampled pulls at 2% throttle position, until the air-fuel line is flat across at the target line. Then he will move on to the next higher throttle position (5%) and do it again... until he has done all the way up to 100% throttle.

Then, the operator will switch to the fuel table for the rear cylinder and move the O2 sensor to the rear head pipe and start over... tuning the rear cylinder at each throttle position through the entire rpm range.

There is also a table for ignition timing, but that's another topic...

3) Wouldn't the changes made to one brand of bike likely be different than the changes made to another brand? For example, if you were dyno tuning a Valkyrie, you would need to know how to adjust and synchronize the six carbs. If you were dyno tuning my 2006 HD softail you would need to know how to manipulate the fuel injection (probably by the addition of an aftermarket fuel controller). If you were dyno tuning a vic, you would have to deal with a different fuel controller and the O2 sensors.
The proper air-to-fuel ratio is the same for all 4 stroke internal combustion engines. If tuning a carbureted bike you would have to disassemble the carbs and change jets, adjust needle heights, and set the pilot screws to achieve the proper fueling. On a fuel injected bike you do this electronically thru the fuel controller. With a Power Commander, the stock O2 sensors will be deleted (they are not used, since the tune will be open-loop).

4) Do dyno tuning experts know all/most of these various tuning methods or do they specialize in one brand?
Either you know how to tune or you don't. Whether it's a single cylinder dirt bike or a 6 cylinder Honda, the process follows the same principals. You make the air-fuel ratio correct. Whatever it takes to achieve that.

The dyno is just a measuring tool that allows you repeatable measurements... like a yardstick... it doesn't do any tuning.
 

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You only need two inputs. A tach signal for rpm and either 1) a tube inserted into the exhaust pipe, or 2) wide-band O2 sensors screwed into bungs in the head pipes.


The only way to tune is to have a means to make changes to the fueling. I will do this assuming there is a Power Commander fuel controller on the bike, since this method is the most common over all brands of motorcycle and the most involved.

You warm up the bike and re-set the throttle points/tps for zero throttle and 100% throttle.
You will tune the front cylinder 1st.
You run the bike at idle and set the desired air-to fuel ratio at the rpm range where the bike will normally idle.
You put the bike in 4th or 5th gear and do a dyno pull at 2% throttle position and save it. The dyno will show a graph through the rpms from the lowest to the highest it revs at that position.

The dyno software will show an air-fuel graph at the bottom like this (The dashed line across the graph can be set to the desired ratio by the operator):




The Power Commander software has a fuel table like this:


Now... the operator will adjust the cells at each rpm, over several sampled pulls at 2% throttle position, until the air-fuel line is flat across at the target line. Then he will move on to the next higher throttle position (5%) and do it again... until he has done all the way up to 100% throttle.

Then, the operator will switch to the fuel table for the rear cylinder and move the O2 sensor to the rear head pipe and start over... tuning the rear cylinder at each throttle position through the entire rpm range.

There is also a table for ignition timing, but that's another topic...


The proper air-to-fuel ratio is the same for all 4 stroke internal combustion engines. If tuning a carbureted bike you would have to disassemble the carbs and change jets, adjust needle heights, and set the pilot screws to achieve the proper fueling. On a fuel injected bike you do this electronically thru the fuel controller. With a Power Commander, the stock O2 sensors will be deleted (they are not used, since the tune will be open-loop).


Either you know how to tune or you don't. Whether it's a single cylinder dirt bike or a 6 cylinder Honda, the process follows the same principals. You make the air-fuel ratio correct. Whatever it takes to achieve that.

The dyno is just a measuring tool that allows you repeatable measurements... like a yardstick... it doesn't do any tuning.

I knew you'd be along to splain things moe better. thumb up
 

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Half Crazy, Thank you very much. You have most certainly and excellently cured my ignorance - at least on this topic. I still have lots of ignorance on other topics but those are for another day. Thanks, again.

G'day,

Vinish
 

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I took my bike to a tuner that is predominately a Harley shop. They said they've done a few Victorys. When I got it back it seemed to run fine but had a bad ping under load. I was unable to find the time to have them redo it so I zero'd everything out and let the Autotune do it's job. Bike runs awesome now!
 

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If i know a good place that dyno's a bunch of Harley's, do you think they can do my Victory as well? Is there anything special that needs to be done with the Vics or can any authorized DynoJet tuner work?
Steve tell us where you live we might know of a good dyno guy to do you right
 

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If the tuner is any good at his job he won't have any issue getting you a good tune.

However somebody who has done a bunch of Vics will know a few more tricks that may help. That may be as simple as knowing that the bike at 50% throttle can run a bit leaner than a harley with the same power or more complicated like knowing that with a timing wheel at +6 you need x% extra fuel at y% throttle. Stuff like that comes from experience.
 

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Give Billy Roam a call 1-530-674-9123 and take a little ride out to Yuba City and have it done right! I promise you will be disappointed in the tune by the Harley guy. Billy has done 4 of my bikes now and I couldn't be happier.

Billy is also approved by Loyd's if that matters to you
 

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So Larry ....... What machine was that the dyno numbers from ??

Peter
 

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Discussion Starter #18
Give Billy Roam a call 1-530-674-9123 and take a little ride out to Yuba City and have it done right! I promise you will be disappointed in the tune by the Harley guy. Billy has done 4 of my bikes now and I couldn't be happier.

Billy is also approved by Loyd's if that matters to you
Awesome! Thanks P.Hunt I can make that trip no problem. Thanks for the tip. I'll be passing right by you and would love to see your bike...it sounds like you've done a lot of the mods I would like get done myself.
 
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