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Do I really need to have my bike dyno tuned?

 A customer downloaded a map from the Power Commander website. The mapping should be close enough, correct?



This is chart showing the AFR (Air Fuel Ratio) recorded with a data recorder on a 2007 Street Glide that had SE 211 cams installed, slip on mufflers and SE air cleaner.  They downloaded a map from the Power Commander website.

                                                                                                                                            Throttle Position


Numbers in Blue are too rich.  Numbers in Red are too lean.
Numbers in White are on target.

Look at how lean the AFR is above 10% throttle.
Some cells are 18.9:1!


There have been very few times that I have seen a download that is acceptable.  Even the "Auto Tune" features on tuning software are not very accurate in the higher throttle positions.  The Auto Tune features will get you much closer and safer than a download, but a true dyno tune will give you the optimum power and fuel mileage.