DCT trouble & solution. Honda NM4 2016 - Honda Vultus Forum
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post #1 of 5 Old 06-03-2019, 10:45 PM Thread Starter
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Thumbs down DCT trouble & solution. Honda NM4 2016

2016 Honda NM4 – Mechanical failure (05/2019)
(-How a simple $8.10 shifting pin caused over $700 in repairs-)

– Vehicle was having difficulty shifting from 2nd to 3rd at certain RPM.
– Problem degenerated to bike shifting out of gear coming off freeway.
– Bike unable to shift back into neutral.

Hello! When I originally purchased my Honda NM4 in 2016 I searched the internet everywhere for information before making the purchase. I didn't find much but I found enough to help make my decision and bought the brand new bike from a local dealership. Very comfortable ride, loved the style of it, and if I was single I would have been picking up girls like I did back in my youth. Everybody would stop and ask me about the bike. Now that said there's some issues with the machine I want to get out there to people doing any research on this particular bike. I wish I would have been told about this.

To start with, this bike has the electronics of a car. You decide if that's good or bad.

The vehicle was taken to an authorized Honda dealership for diagnosis and repair. Once able to read the trouble codes in the computer, the dealership was unable to determine the issue.

Following the Honda repair manual step by step to diagnose the problem based on what the trouble codes did tell us it became clear that this was a mess. The actual process of trying to diagnose the issue only involved replacing one part after another part. Example: Replace part A. If that doesn't fix the problem then replace part B. If that doesn't fix the problem then replace part C, and so on. The issue with that method of fixing anything is obvious, you pay for the labor and parts for each individual repair job. The real kick in the shorts comes when you realize that you are quite possibly throwing out good parts you did not need to replace, or purchase. Honda does NOT allow for parts to be installed on a vehicle for testing purposes. Once you put it on the bike, you've bought it whether or not you needed it. On to the problem. This whole process took over 22 days. 05/09/19 to 05/31/2019. This was just a stupid amount of time to figure out what a problem is for any type of vehicle. Especially a “modern” vehicle. My old 2001 BMWR1200C which had over 167K miles on it, was easier to diagnose and I used to think it was the pinnacle of motorcycle tech. I'd take it in for work, the techs would plug it into a computer, the issue was discovered and repaired. I'd usually get the bike back in two or three days depending on the availability of the parts. Then there is this DCT ( Dual Clutch Transmission) monster of an NM4.

At the dealership, they contacted the Honda Tech support almost immediately. Let me say up front that the service guys were great. I didn't feel for two seconds I was dealing with incompetent or dishonest mechanics and I've dealt with those types before. At first it was thought to just be my battery. We replaced it. I needed a new battery anyway. But it wasn't low voltage or anything like that. Next we replaced a sensor. That cleared some of the trouble codes but the shifting problem persisted. A Honda Tech came out to the dealership personally to look at the bike and explained to the techs that with the DCT bikes there has been an occasional issue with a bolt called the “Shift drum center bolt” which can be located on page 65 of chapter 11 of the Honda service manual. It was then determined that indeed the issue with the gears shifting was due to this bolt coming loose.

Not broken, not damaged, just loose !

I even have the replaced bolt in my possession. It looks great. Since the bike was already apart the Honda tech recommended the bolt be replaced along with other o-rings. The parts were cheap and the labor already done so the tech was correct in wanting the parts replaced which I agreed to. In looking at the old center bolt, there is absolutely no damage to it. It just came loose.
The dealership then applied mechanical adhesive to the bolt when they installed the new one. It won't come loose a second time. In fact the techs were clear that if that simple little thing would have been done at the factory then this bolt would NOT HAVE COME LOOSE ON ITS OWN over time.

So my beef now is that a part that didn't even break instead just came loose because somebody who designed the machine never thought of it coming loose. The fact that this issue is now happening with other vehicles with a DCT is troublesome. Another problem I have with this vehicle is that Honda designed this machine and despite a Honda trained tech armed with the repair manual in hand the issue could not be diagnosed in a reasonable amount of time and required an obscene amount of labor ($100 an hour) to figure out what the issue was. In the end it took a senior tech directly from Honda to come out and explain the problem and that he'd even seen other vehicles with the same problem. Before buying one of these ask yourself what happens when another little thing goes out on this model? Another $700 repair bill to find a simple problem? I'm asking myself that lately. Now before any of you might say that all vehicle's have their issues, or that any motorcycle with 58,000 miles on it will show some wear and tear I will point out again that there is no systematic method of diagnosing this problem other than going from one step to the next while replacing parts along the way that you may not need. I'll also refer back to the BMW I mentioned earlier. That technology is over FIFTEEN years older than this DCT bike and despite that the computer systems they had back in 2001 were good enough to pinpoint issues on the bike. This 2016 NM4 system couldn't do that. It took a very experienced factory tech to come out to the dealership. On top of that it was only because that particular Honda tech had already seen other DCT machines with the same loose bolt issue that he knew what the problem was.

So the grand total for this loose bolt was: $891.32 We do need to subtract the new battery, I was in need of one and planned on replacing that later this year anyway so that was $139.99.

Subtracting that leaves us with a grand total of $751.33 for a loose bolt. Think on that folks. $750 bucks to figure out a bolt came loose that should not have ever come loose in the first place and could have been prevented by the factory just using a simple bolt adhesive. That's what these new high tech Honda NM4's offer us dedicated riders. I went through the entire Honda manual and there is nothing that would help a tech figure this one out. They would just go from one part to the next part until they find it. I now have a “350 degree sensor” that cost me $137.72 sitting in a box. A new one was put on the bike but concerning this old one we just don't know if it is bad or good, they can't test it if you can believe that. I literally may have spent $137.72 on a part I didn't need, but the repair manual said replace it and if that didn't work go on to the next step.

On the issue of labor, the guys at the dealership did me a solid and kept it at a flat 4.5 hours but I know full well they put in more time than that and even had that other factory tech come out. If the dealership had tried to stick me with the actual time spent it would have been double. I took the kid a twelve pack just to say thanks for his efforts. As for me, I've owned multiple bikes over the thirty-five years I've been riding. I have over 350,000 miles riding in a saddle. Most of that on just that old BMW but another 58K on this NM4. The rest of those miles are spread out over Yamaha's, Kawasaki's, a Suzuki and a Harley. While those are all gone I did manage to hang on to my 1978 Honda 750A Hondamatic. Ironically that bike is the original DCT in a way, the ancestor to the NM4.

I hope this was helpful. If you find your NM4 is not shifting correctly then that bolt may be your problem. Maybe you can save yourself the time and wasted money with this information. If you are somebody looking at buying a NM4, the choice is yours but I'm not happy with this DCT.
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post #2 of 5 Old 06-04-2019, 10:21 AM
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Thank you for the extremely well-written post--awesome.

I'll add a bit here since this forum (and interest in the NM4) has become pretty sparse (at least it's something to read).

As Things Get More Complex Problems Are Harder To Diagnose

Look at a 1931 Harley-Davidson Flathead engine: fairly simplistic with loose tolerances, low compression and runs on any old fuel. Norton: Pretty much anything that can go wrong can be fixed on the side of the road with minimal tools and some spare parts. 1953 Royal Enfield Bullet 500: Vibrates like a Norton, breaks as often, also easily fixed. The commonality is: They're simple to fix. They break often. They leak oil. Maintenance is somewhat 1:1 being 1 riding hour = 1 wrenching hour. They didn't have much power or fuel economy for their weight compared to modern engines. And a huge bonus: They're cheap to build if the demand is there: Bullet 500: Cheap, $6K for a whole new bike. S&S modernized Harley Knucklehead: Expensive, $10K just for a new engine, if you can get one.

Current Bullet 500s are made on the same machines that are now that much more worn out, so the older REs are actually better made than the new REs. Each iteration of Harley engines fixes major problems with previous engines, starts easier, runs better, etc. Each is more complex than the last. The new Milwaukee Eight still has problems with overheating, even though the valves are liquid cooled on the 114, the rest is air and oil cooled.

The Honda CB750 was the first motorcycle to break with convention and modernize "everything." It is arguably the first "superbike." 4 cylinders, 4 carbs, tight tolerances, so fast they decided to use rotor technology from race cars instead of drum brakes. A much more complex machine with much more performance.

Simple Solutions Fix Complex Problems

Posted this on another forum:

Things learned with time:

- The harder something is pushed the faster it tends to break.

- Factory items tend to be very, very reliable compared to aftermarket.

- It's wise to figure out the most probable causes, but start by testing the easiest suspects to test first.

- Diagnoses are based on symptoms, solutions are based on causes--basing a solution on a symptom without eliminating the cause doesn't negate the problem.

If Honda had released a service bulletin you might have been able to fix this yourself.

I'm No Longer Excited About Getting An NM4

Forum participation has mostly died off. Honda releases "new models" every other year, which isn't bad by itself though does show Honda's lack of interest in the bike. NM4 styling is dated to late 1970s and could use a makeover, much like the Golding received in 2018. While a 2018 Goldwing is around $32K new, it does add a ton of touring features, and dumping $12K into an NM4 goes a long way toward buying a Goldwing instead. The local Honda dealer has most likely worked on Goldwings for years, but probably not even seen an NM4, meaning repairs carry the cost of the learning curve at $110/hour, and your pocket bears the burden.

Sure, a NM4 will get a lot of attention wherever you go, at least for as much attention as 1970's styling can get. "That '70s Show" used to be popular too, but interest waned in 2006, 13 years ago. Did the NM4 get the DTC updates? Don't know.
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post #3 of 5 Old 06-04-2019, 10:38 PM Thread Starter
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Love your post.

If that bolt in my post was better secured at the factory, it wouldn't come loose. You'd think things like that are something Honda would be interested in. To me it's also a safety hazard. Sounds like just enough others are having issues too with Honda's DCT. So much for a flagship.
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post #4 of 5 Old 06-12-2019, 09:14 AM
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I kind of wandered around a bit for those who don't know bikes well, but the bottom line is:

Old & Simple = Unreliable but cheap and easy to fix: Royal Enfield still makes the Bullet using the original factory machinery from 1953. The machines are now old and worn out, tolerances are loose, the resulting quality is horrible, but the technology is simple and easy to repair. The Bullet is one of the best selling motorcycles in the world because it's cheap and easy to repair, not because it runs poorly, breaks often, and has poor fuel economy.

Somewhat Recent & Complex = Somewhat reliable, relatively easy to fix: Every 10 years (on average) Harley releases a redesigned engine based on old technology. Every iteration is slightly more complex & harder to repair, but is more reliable and lasts longer between rebuilds.

Breakthrough Technology = Reliable, repairs aren't so easy: Honda's CB750 set the stage for modern bikes. Because there are so many the prices are cheap and people throw them away, but they're really an under-valued bike that over-all out-performed other street bikes. They're not bad to work on, but they're not super easy to wrench either. They do run a long time though, 70K miles or more.

Cutting-Edge Technology = Awesome Reliability (generally), Hard to Fix: The Honda Africa Twin and 2018 Goldwing stand out as quiet, reliable, requiring quality fuel but not much of it. If any little thing goes wring it can be a major mess, however, the Goldwing regularly runs 120K+ miles without issue, which is amazing given there's 6 cylinders and all the supporting parts vs. the Bullet's one.


Regarding your plight, why did they not release a Service Bulletin??? It would have been so easy, fast, and inexpensive to check the bolt. And therein lies a major problem within Honda: no love for the New Machines (NM-4) It's a very complex and tight-tolerance machine that is so hard to fix that just troubleshooting is reduced to: try a new $200 assembly and see if that fixes the problem, if not, try a different $200 assembly--sooner or later you'll have replaced the problem...


It would be an incredible machine if Honda updated the styling, put a sport-tuned engine in, and redid the DCT software to work better. It's a sportbike, make it sporty! And add an awesome passenger seat, since this begs for family/friends/others to want a ride. And give it a center-stand--owners can always take it off.
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post #5 of 5 Old 07-01-2019, 12:57 PM
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Hi Ghost!

Thanks a thousand times for this useful story! Hopefully lots of riders will read it and learn.

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