The infamous GL1800 stumble caught on video

[glarson3]

This is a video I took today of the infamous GL1800 stumble. Please let me know if this is what others are experiencing as well. Some background. The bike had been ridden a short distance, then parked outside for about 30 minutes. Ambient temperature outside was ~75 degrees. Immediately after stopping the video I hit the 'info' button and it displayed the temperature as 86 degrees. I tried to get a shot of my throttle showing that there was no movement of the throttle though you can clearly see the RPM's fluctuating.

http://youtu.be/-RWc4ZxCcKw

[Cruiseman]

That is not what mine is doing. Your bike temp was much warmer than when mine stumbles.

[glarson3]

That is the top range of when it stumbles. If it's much higher than that, it won't stumble. My point was that many people have said, just let your bike warm up to above the bottom line, and it won't happen(actually that's what Honda says), but as the video shows, that's not the case.

Cruiseman, do you think that your ECM reflash had any effect on when/how this happens, and is the fluctuation in RPM's what you experience, just in a slightly different temp range?

[Cruiseman]

Cruiseman, do you think that your ECM reflash had any effect on when/how this happens, and is the fluctuation in RPM's what you experience, just in a slightly different temp range?

No. Mine still happens at exactly the same temp and "location" as it always has. It is slightly less pronounced, but it is still there.

[Shoeman]

Mine only stumbles under load, right around 1700 rpm any time the temp is below 1/3-1/2 way. No ghost throttle other than high idle for about 30 seconds

[glarson3]

Mine has nothing to do with load. As you can see, it's in neutral, but mine seems to be right around this location on the temp.

[530ktm]

Mine has nothing to do with load. As you can see, it's in neutral, but mine seems to be right around this location on the temp.

That is strange, mine does nothing like this so I am not sure if mine even is haunted by the stumble. The only time I have ever experienced anything is when it is cold and I start off from dead stop with a light throttle and is completely gone when warmed up. That fluctuation in RPM like that would have me concerned a bit.

[Shoeman]

Mine has nothing to do with load. As you can see, it's in neutral, but mine seems to be right around this location on the temp.

Sounds like a whole different issue.

[glarson3]

At least now, maybe we can get some consensus of those who have complained about the stumble, if we're really talking about the same thing. This is the exact same behavior I've been experiencing since very soon after my purchase. The first time I experienced it, I pulled over(wife to be on the back) and stopped. We were on our way to the chapel to be married. She though I had cold feet. Now I can prove to her it wasn't.

[Spencer]

My theory : In Japan motorcycles over 250cc must meet strict emissions regulations and their tests include a "hot test" as well as a "cold test" along with an actual running test that simulates slower speed riding. With this showing up after the move to Japan, many Honda cars having a "stumble" until fully warm, and the 1800 platform having a rather inefficient head design, I fear it is a designed in necessity to pass so not seen as a concern to Honda and much like their car owners have discovered the only remedy is to fully warm it up.

[dxlnt1]

I dont have the years bikes that you guys are having the "stumble" issue with. But just trying to understand. That is not a stumble. That is seemingly hunting for idle. Then it takes off and over revs? Scary, but could be any number of things.

But when that happens, does the bike actually lose power? Or is it just "a surge?"

A video with possible solution. Bad alternator as solution.

[HBarlow]

I dont have the years bikes that you guys are having the "stumble" issue with. But just trying to understand. That is not a stumble. That is seemingly hunting for idle. Then it takes off and over revs? Scary, but could be any number of things.

But when that happens, does the bike actually lose power? Or is it just "a surge?"

A video with possible solution. Bad alternator as solution.

I agree.

The symptom described clearly by the op is usually called "hunting" rather than stumble. It occurs when engine rpm varies randomly above and below a given engine speed.

A "stumble" is normally felt during acceleration, usually at low speed, when acceleration is momentarily interrupted as the throttle is opened. It may be accompanied by a spit or sputter sound from the exhaust. Probably caused by an excessively lean fuel mixture that fails to combust.

[Tony in AZ]

The early years of the 1800 had that same RPM jump at certain throttle position. My 2004 bike had that. At any engine temp. I was told by several folks that was where the EFI mapping was trying to switch from low speed to high speed mapping.

My 2013 has a "blubber" as the temp gauge needle hits the first small line. I can make the bike blubber every time the temp is at that mark. In gear, riding, it is very dangerous to hit this blubber spot as the bike will try to fall over if in a low speed turn. I've had this blubber happen coming out of a restaurant after eating. Fire the bike up. Let it run as we get our gear on. Ride across the parking lot and the bike blubbers like the old days with a carb on a car where the choke was still hanging closed some ( I'm a mechanic for decades) . The bike is not rich mixture, it is lean when it blubbers. I learned on early TBI engines when the fuel pressure was low, the engine blubbered like it was too rich, when the engine was actually lean. It was a learning curve for this old hotrodder - mechanic on the EFI stuff as the OEMs installed EFI on everything

Dang odd my Honda cars have never blubbered like this bike does. In fact I;ve never had an EFI vehicle blubber like this bike does. Sad programming, mistake, wrong sensor inputs, something. Honda has eff'd up this bike throttle response IMHO

[Hammer]

My 01 works as advertised , no stumble

[dxlnt1]

I agree.

The symptom described clearly by the op is usually called "hunting" rather than stumble. It occurs when engine rpm varies randomly above and below a given engine speed.

A "stumble" is normally felt during acceleration, usually at low speed, when acceleration is momentarily interrupted as the throttle is opened. It may be accompanied by a spit or sputter sound from the exhaust. Probably caused by an excessively lean fuel mixture that fails to combust.

So could it be an issue with ignition timing.

The early years of the 1800 had that same RPM jump at certain throttle position. My 2004 bike had that. At any engine temp. I was told by several folks that was where the EFI mapping was trying to switch from low speed to high speed mapping.

My 2013 has a "blubber" as the temp gauge needle hits the first small line. I can make the bike blubber every time the temp is at that mark. In gear, riding, it is very dangerous to hit this blubber spot as the bike will try to fall over if in a low speed turn. I've had this blubber happen coming out of a restaurant after eating. Fire the bike up. Let it run as we get our gear on. Ride across the parking lot and the bike blubbers like the old days with a carb on a car where the choke was still hanging closed some ( I'm a mechanic for decades) . The bike is not rich mixture, it is lean when it blubbers. I learned on early TBI engines when the fuel pressure was low, the engine blubbered like it was too rich, when the engine was actually lean. It was a learning curve for this old hotrodder - mechanic on the EFI stuff as the OEMs installed EFI on everything

Dang odd my Honda cars have never blubbered like this bike does. In fact I;ve never had an EFI vehicle blubber like this bike does. Sad programming, mistake, wrong sensor inputs, something. Honda has eff'd up this bike throttle response IMHO

So has or will anyone try the alternator thingy? Especially if its consistent, persistent and reproducible! If the alternator is the issue, wouldnt that be mud in Honda's face? Im just curious.

[glarson3]

I dont have the years bikes that you guys are having the "stumble" issue with. But just trying to understand. That is not a stumble. That is seemingly hunting for idle. Then it takes off and over revs? Scary, but could be any number of things.

But when that happens, does the bike actually lose power? Or is it just "a surge?"

A video with possible solution. Bad alternator as solution.

Just so it's clear, the throttle was attempting to hold steady at ~1800, and was dropping about 500, and going back to 1800. I'm not sure how the alternator could play into this, but the bike has been doing this since it was just a few weeks old, so if it's the alternator, it's been bad since week 2 of ownership, and hasn't 'failed' yet.

The bike is actually losing power, and when I first experienced it, I thought the bike was going to die. It's not until you apply additional throttle that the bike takes the full input. e.g. You're trying to hold 1800 RPM's, the bike 'stumbles' to about 1300 RPM's, then you apply throttle to bring it to 3000 RPM's, and you suddently go from 1300 RPM's to 3000 RPM's.

I described it as a stumble because it's not like the normal 'hunting' I've seen where the RPM's fluctuate maybe 200-300 RPM's, and most notable at idle. That behavior I've seen on most of my vehicles.

[530ktm]

I was curious if you have taken this to the dealer for them to hear what it does and see what they have to say about this situation.

[glarson3]

I was curious if you have taken this to the dealer for them to hear what it does and see what they have to say about this situation.

Ironically, I reported this problem when the bike was still under warranty, and they said they could not duplicate the issue. My bike is no longer under warranty, but the behavior still exists, and now I have video evidence, so perhaps Honda will see what they can do to fix it. I actually went to Honda on Saturday, but did not show them the video. I remembered it right after I got home. I plan to show it to a dealer, open a case with Honda and see how things go from there.

[Jack]

I'll plan on keeping my perfectly smooth '06 a while longer.

[dxlnt1]

Just so it's clear, the throttle was attempting to hold steady at ~1800, and was dropping about 500, and going back to 1800. I'm not sure how the alternator could play into this, but the bike has been doing this since it was just a few weeks old, so if it's the alternator, it's been bad since week 2 of ownership, and hasn't 'failed' yet.

The bike is actually losing power, and when I first experienced it, I thought the bike was going to die. It's not until you apply additional throttle that the bike takes the full input. e.g. You're trying to hold 1800 RPM's, the bike 'stumbles' to about 1300 RPM's, then you apply throttle to bring it to 3000 RPM's, and you suddently go from 1300 RPM's to 3000 RPM's.

I described it as a stumble because it's not like the normal 'hunting' I've seen where the RPM's fluctuate maybe 200-300 RPM's, and most notable at idle. That behavior I've seen on most of my vehicles.

Not to argue but just to add another perspective. My perspective on it is the throttle was not doing anything. Your hand was sitting still on the throttle with no input being made. Yet the engine was hunting and surging. Its rational to me that it COULD be electrical or timing. The FLAT spot in throttle input also leans to timing. If these bikes haves have self adjusting timing all governed by ecm, true voltage COULD be paramount to that operation. And if Im not mistaken, isnt the alternator responsible for maintaining voltage/current since no external voltage regulator on bike?

Remember the old cars with points and condensor? This problem was common after a tune up. You then adjust points gap and timing to correct.

Hope Im not offending anyone with my comments or questions.