Dyno Tunning
This article is going to help explain dyno tuning and other alternatives that you can explore. Any bike that has had engine modifications needs to have the bike’s computer remapped. A carbureted bike would need to be re jeted. Please read the article titled “Carburetor vs Fuel Injection”. Your fuel injected bike has a Computer (ECM Electronic Control Module) that tells the injectors how much fuel to flow into the cylinder. The ECM also controls the ignition system. I am going to mainly discuss the injection part of the ECM.
The bike manufacturers mass produces the motorcycle and engines. These bikes and engines will basically be the same for each model. In theory they are close enough in design that each model can all have the same ECM program. An engineer develops the Master Program and then it is used to program each bike that fits that program. Any time that you modify your engine, it changes the parameters and the program can no longer provide the correct amount of fuel that will allow your engine to run safely without damaging it.
You can manipulate the program of your ECM by using programs such as the more commonly known “Power Commander” or “Screanin Eagle Race Tuner”. There are other programs out on the market and also “self tuning ECM systems” that seem to work well. I’ve heard different people that believe that one brand will be able to produce more power than the other. The two more common programs both will have the ability to map your bike correctly. Neither one can give you more power than the other one. Someone that tells you that "one will give you more power than the other", does not understand how the system works and the truth being, does not know how that program works. They both are very similar when it comes to basic mapping. Now the one that is better is the one that offers more adjustable parameters that can be manipulated. I prefer the SE Race Tuner because it offers more systems in the ECM that can be changed. It also offers a data recorder that lets you look at everything that the ECM sees.
I will be using the SE Race Tuner for 2007 and later bikes for demonstrations. You can apply these basic tuning techniques to either of the tuner programs. Bikes that are 2007 & up have a closed loop fuel injection system. This system incorporates oxygen sensors in the exhaust that will help to self adjust the A/F mixture. The term "Closed Loop" refers to that the O2 sensor is online (turned on...now working...). These are narrow band O2 sensors (old technology). You probably are thinking, if it is self adjusting, you shouldn’t have to be remapped. This is not correct. The O2 sensor creates it’s on voltage that is sent to the ECM where the ECM processes the voltage into usable information that tells the injectors how much fuel to deliver. The problem with narrow band O2 sensors is that their voltage signal is from 0 – 1 volt. .5 volts being the optimum A/F ratio of 14.7:1 which is desired for EPA regulations and better fuel mileage. This gives you a very narrow range of adjustment. The wide band O2 sensors have a 0 – 5 volt range with 2.5 volts being optimum A/F ratio. If the A/F ratio is out of the O2 sensor’s voltage range, it cannot communicate the correct voltage reading to the ECM. This means that the A/F ratio has to be adjusted to fall with in the O2 sensor’s voltage range. The other problem with the 2007 ECM is that it will only adjust the mixture to 14.6:1 A/F ratio when in closed loop. It would be nice if you could program the ECM to automatically adjust the mixture to a specific ratio that you want such as 13:1 A/F ratio. You can use this system to get better fuel mileage at cruising speeds but, it will have to be mapped to run richer where richer is needed.
SE Race Tuner
The first thing to do is to go to “Set Up” then click on “Advance Mode” under “Basic and Advanced Modes”. Go to the “Table Selection” tab and click on “ECM Tuning Constants”. Here you will need to input you engine specifications. Now go to the “air fuel ratio” table under the “table selection” tab. Change all of the cells to 13.0:1.
It’s time to do some dyno tuning. Start with “VE Rear Cylinder” under the “Table Selection Tab”. Make sure that the engine is at operating temperature. Note: It helps if you make a note sheet that looks like the table that you are adjusting, to put your actual readings on. You can do this easily in a spread sheet program and save it for future mapping jobs.
Another tip that helps is to put masking tape on the throttle and tape on the turn signal housing to mark you throttle positions. Mark a reference mark on the turn signal housing tape.
Note: The ECM reads the voltage from the TPS (Throttle Position Switch). 1/2 or (50%) throttle position is not necessarly located half way between 0 and 100 on the masking tape. The half way point between
0 and 100 will probably be read 60% - 70% by the ECM. The paragraph below will explain how to mark the correct throttle positions on the masking tape.
Go to your “Data Mode” program that comes with the race tuner. With the data link connected between the bike and your PC, click on the “File” tab, then click on “Record Data”. (Both ignition switches must be on). It will now ask you to save this file, so put in anything for a file name. Now click the “Start” tab. You can now minimize that window. With the Data Mode screen showing, you can see “real time” information. Look for “throttle position %”. Now you can mark your throttle positions on the tape that you installed on the throttle. Mark the same TP (throttle position) as you will be using on the VE Front Cyl. screen (Mark 5%, 10%, 20%, 30%, 40%, 60% 80% and 100%).
Start making your dyno runs at the lower throttle positions and working your way up, adjusting the AFR to 13:1. After you have adjusted the AFR to 13:1 on these throttle positions, you can now blend the other throttle positions to average the ones that you corrected. Example: At 3000 RPM the 20% TP = 81.5 and the 30% TP = 75. Average the two and enter that figure to the 25% TP. This will save time by keeping you from having to run the dyno through all of the throttle positions. Now do the same with “VE Front Cylinder”. You can click the “View Graph” tab and see the table in 3D. The table shouldn’t have aggressive dips or spikes. You can determine which cells have spikes and dips and correct the cells while viewing the 3D graph. This is another smoothing technique.
After you have finished with the VE front and rear cylinder tables, go to the “Air fuel Ratio table and put in the A/F figures that you desire. In theory, if the engine specs. were put in correctly earlier, the A/F ratios should match the actual A/F ratios. Of course this is the theory but there is always some fine tuning that is necessary. Always make your fine tuning adjustments in the appropriate VE table, because changes to the A/F table will change both front and rear cylinders. On 2007 models, every cell that has 14.6:1 will put that cell in the closed loop system. I suggest that you put 14.6 in cells where you are cruising in.
There are many other areas in the ECM that can be manipulated to improve drivability.
These are also located under Table Selections.
Advance or retard the ignition timing any where that is needed, front or rear cylinders, improve warm up enrichment problems, adjust the engine idle and cold start up idle. The newer versions offer Accelerator Enrichment and Deceleration enleanment. This can help correct the dead spot on sudden throttle openings, very much like an
accelerator pump on a carburetor. The deceleration enleanment helps eliminates exhaust pops on deceleration.
Taking Advantage Of The Data Recorder
The more that you use the Data Mode option, the better you can use it and realize the potential that it has. Open the Data Mode program. Go to File and click on Record Now. It will ask you to save in a file, so make up a file name. You can now click on the record Start tab. This will start your recording secession. You must click on the Stop tab to stop the recording Before You Turn The Ignition Off .
You need to customize the “Item Value” screen at the lower right corner above the “Restore Graph” tab. Double click on one of the four items and it will take you to a screen where you can change the item to the item that you want to see. You can do this to all four items one at a time. The two that you will use the most is Engine Speed and Throttle Position.
Now that the basic tuning maps are completed, you can fine tune any running problems that the bike has by using the other tabs located under “Table Selection”. If the bike runs rough when the engine is cold, it may need to be richer or leaner during warm up. You can connect the data recorder, (A laptop is needed) and start recording before you start the engine. Now ride the bike while the recorder is running. When the bike starts to run rough, snap the throttle. This will mark the spot on the recorder that need to be corrected. You should see the throttle snap spike on the recorder graph. Scroll you mouse over the spike or click on the spike and it will show all of the engine parameters at that point and time in the graph above. Here you can read what the temperature is of the engine where the running problem occurs. Now you can go to the Tuning Mode under Table Selection, click on Warm Up Enrichment and adjust the cell beside of the temperature where the problem occurred.
You can also use the recorder to determine if spark knock occurs. Look at “Knock Retard” when playing your recording. If spark knock occurs, it will show up here. If you see where the ECM had retarded the Timing, can also see what the RPM and MAP load that it occurred at. Now go to the Tuning Mode, under Table Selection and then Spark Advance, go to the corresponding cells with the RPM / MAP information that was recorded lower the timing the same amount that it was retarded.
In theory on the 2007 bikes, you could also see where the mixture is by looking at the O2 sensor voltage. The problem with this is that the narrow band O2 sensors are not accurate enough to work properly this way. It would possibly be feasible if it had wide band O2 sensors.
The recorder also has some other very helpful features. Under the tab “View” you will find DTC Codes, Speed / Distance Calculator, Quarter Mile Calculator and Dyno Graph. If your check engine light comes on, you can read the diagnostic trouble codes with the Data Recorder.
The speed / distance calculator is very handy. This will let you compare before and after modifications. You will need to record before and after you make your modifications. The best way that I have found to find a straight level road that has very little traffic. Start the recorder, ride the bike in 2nd or 3rd gear depending on how fast you can ride on this road. Basically start your recording as you would normally do. Ride the bike and go to full throttle at 2,000 Rpm and let off at whatever you have the rev limiter is set at. After you make your run, turn the recorder off and click on the Speed / Distance Calculator Tab. You can scroll your mouse pointer along the line graph and click on the line graph where you want to start your “Record ”. Boundaries suggest setting the “Set Begin Record” at the point that you go to full throttle (at the predetermined 2,000 Rpm). Set End Record to maximum RPM. Now click the Calculate tab. This will tell you the distance it took to make the run, the elapsed time that it took, and the average G force.
After you make your engine modifications, record the same way as you did before. Now you can compare the two runs. The reason to make your runs while the bike is moving such as 2,000 RPM instead of starting at a stand still is that starting from a dead stop your statistics will be inconsistent because of things such as wheel spin and gear changes. You can also click on the Dyno Graph tab which will provide a dyno graph. I have found that this graph is not accurate but, can be useful to compare runs.
This is an example of the Speed / Distance Calculator. This is a 2003 Softail Standard that I replaced the engine oil from HD 20w 50 to a AMS Oil 15w 40. The left chart shows before the oil change. The right side shows the oil change with a special oil. Notice that it was .336 seconds faster. It traveled 26 feet shorter distance to reach the same speed. It gained .032 "G"
This is the dyno portion ot the Data Recorder. There again, the numbers are not correct (They are low.), but you can use it to compare before and after modifications. This was taken from the recording above. The first one is before and the second one is after.
Another way that you can map your ECM without a dyno is to use a data recorder such as the Innovate LM1 recorder. To use this recorder it will need to sample the exhaust. The best way to do this by installing O2 sensor bungs in the exhaust. After setting up the LM1, you can ride the bike and record the AFR at any RPM, TP or Map load. The neat thing about the LM1 is that that the graph can be made to correspond with your tuning software.
You can set up the chart to match the Tuner. The pinkish numbers is the actual AFR that the engine is running at. Notice that the AFR is about 13:1 at 20% TP and 7,000 RPM. This is a great tool and makes tuning very easy. The longer that you record, the more cells that are filled in.
It also provides a line graph and you can record or view real time engine data on guage like console.
You can find out more about the LM1 at: