Wednesday, July 9, 2014

ECU Reflash

Boosting your Goldwing's performance

If you own a 2012 or newer Goldwing or F6B you may already be familiar with the annoying "stumble" that can occur when your bike is cold. Basically, this is a loss of power that can occur before the engine is completely warmed up. It is not only annoying, but potentially dangerous. Imagine leaning in to a turn, applying the throttle and nothing happens. Without the momentum necessary to maintain gyroscopic integrity, you could drop the bike. And, some owners have reported doing just that!

Even though scores of owners have complained to Honda, they apparently are not going to do anything to address the issue. Since this problem really only began showing up on the 2012 and later Goldwings (and F6B) it was surmised that Honda must have altered the programming of the ECU (Electronic Control Unit), most likely to meet stricter EPA standards. I don't claim to fully understand everything the ECU does, but it basically is the computer brain that controls the fuel/air mixture of the fuel injection system, ignition timing, and other stuff.

The ECU on the Goldwing is technically non-programmable. However, Don Guhl of Guhl Motors recently figured out a way to "hack into" the ECU and re-program it with modified maps that can alter the way the bike performs. Guhl offers three different program options for the 2006 and later Goldwings. The first option basically gets rid of the stumble and is the most modest program, the second choice is a bit more aggressive and should deliver performance gains along with better fuel mileage. The third is the most aggressive offering the highest level of performance. However, Guhl recommends the use of Premium fuel with the third option.

WARNING! Having your ECU modified will void your Honda factory warranty. Of course, it would only void your warranty for damage to your engine that could be related to the re-flashed ECU. So, if your final drive fails, that would still be covered.

If you decide to have your ECU re-flashed, you will have to remove the ECU from your bike and ship it to Guhl Motors. Once they receive it, they should be able to ship it back to you the same day. The cost of the re-flash includes overnight shipping. In my case, I shipped the ECU overnight on Tuesday and had it back in the bike on Thursday evening. The cost for the service is $375. Also, Guhl promised to return your ECU to the factory program for free if you decide you do not like the performance.

To remove your ECU, you will have to remove the left side of your shelter. The ECU is located on the left side of your center glove box unit under a rubber strap. I have a video that shows how to remove the top shelter on my DVDs or, you can rent a single On Demand video showing how to do this (see below). I have a free YouTube video showing how to remove the ECU (watch YouTube video).


After spending nearly two weeks with my new re-flashed ECU from Guhl Motors I now feel qualified to report on how the Goldwing performs. I just returned from a 738 mile trip to West Texas (and back). And, while the bike does not perform any differently cruising down the highway, I wanted to know the impact on highway mileage, if any.

I should point out that I only have about 80 miles of in-town riding on the new ECU, not really enough to give meaningful mileage figures.


Let's get one thing out of the way right up front: The low-speed stumble is gone! The re-programmed ECU drives a stake through the heart of one of the most annoying, and unsafe, characteristics of the 2012-2014 and F6B Goldwings. I have the Level 3 reflash, which is the most aggressive program.

For the first time since I have owned my 2012, my bike felt like my beloved 2007. Throttle response is greatly improved and it just seems to pull stronger throughout the RPM range. I have seen charts that show a 3 to 5 horsepower increase, but it feels more like a 10-15% improvement.

Even with the most aggressive program, Guhl claims that very conservative modifications have been made to preserve the reliability of the engine.


Guhl Motors recommends Premium (93 octane) fuel with the Level 3 program, mostly for increased performance and mileage. On my recent ride to West Texas, I decided to run Premium (93) on the outbound leg and Regular (87) on the return leg, then compare the results.

Premium Gas (93 Octane)

Fill Up Miles Gallons MPG
1 139 3.44 40.36
2 103 2.40 42.83
3 115 2.72 42.28
Average 41.82

Regular Gas (87 Octane)

Fill Up Miles Gallons MPG
4 116 3.09 37.54
5 103 2.58 39.98
6 148 3.69 40.06
Average 39.19

As you can see, there is a 2.63 mpg increase with Premium fuel. However, driving conditions on the return leg (Regular gas) were a little different. It was about 10 degrees hotter outside and I had a much stronger headwind.

I went back into my Fuelly ( records to compare with my March trip to Amarillo. The ride from Dallas to Amarillo is roughly the same distance and similar road conditions. On that trip I averaged only 38.92 MPG. So, even after the Guhl re-flash with Regular gas, my mileage has improved.

Granted, this is not a scientific mileage measurement, so I am not prepared to say that you will improve your gas mileage with the ECU re-flash. But, I am prepared to say that I don't think my mileage is any worse than before, and performance is definitely improved. If you are looking for better mileage with only a modest improvement in performance, you may want to consider the Level 2 program from Guhl.


Because a modified ECU has the potential to void your Honda factory warranty, I cannot in good conscious recommend the modification. However, I am glad that I did it on my 2012 Goldwing. I am convinced that the low-speed stumble is a dangerous characteristic of the 2012+ Wings that Honda refuses to address. The ECU re-flash from Guhl Motors definitely solves that safety concern. For more information, contact Guhl Motors at Make sure to mention that you read about it from Cruiseman's Garage!

If you have had your ECU modified, please post your results to my Facebook page.

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