Lumpy Idle

[RossKean]

Perhaps I should call this more of an observation as opposed to a problem.

I have a new-to-me 2011 FJR with 60,000 km (37,000 mi) on the clock. I am noticing that there is an instability in the idle speed. Set just over 1000 RPM when warm, the idle varies perhaps +/- 50 RPM - maybe 2 Hz rate or so. Creates no issues for me, doesn't affect rideability. Lots of power and no surging at higher RPM while riding. Fuel economy is good. No Power Commander or other fuelling modifications. Staintune exhaust (possible factor?). The bike had not been run much in a couple of years but the original owner said it has always done that. It has had one Ringfree enema and 6,000 km of riding since I got it two weeks ago. Setting idle up a bit (1100 RPM) makes it a little less noticeable but it is still there. Plugs are relatively new NGK CR8EIX iridium.

I wouldn't think anything of it other than the fact that I have not especially noticed this with other FJRs and my '07 didn't do it in (almost) 300,000 km. The lope or surge is very regular and repeatable so I can't imagine that it could be a throttle position sensor issue. I would expect that a problem associated with a clogged or otherwise compromised fuel injector would not be as repeatable and there would be other symptoms.

A few things occur to me to be worth checking next time I am under the tank but I would appreciate other suggestions:

• Check for missing or cracked rubber TBS caps
• Look for other possible vacuum leaks (using propane or starting fluid)
• Redo TBS
• More Ringfree or Seafoam
• Check plug wires and seating of connectors
• Check that O2 sensor is connected
• Conventional spark plugs?
• Ignore it and buy better earplugs?

Thanks

 

[Fred W]

I have noticed this to varying degrees on other FJRs. My 2005 did it quite a bit if idle was set up to 1100 rpm, which is where I mostly kept it. I attribute the variation to lean stumble as the idle fueling is set lean from the factory, and if the O2 sensor is still installed, the closed loop ensures the fuel ratio is lean.

Fooling around with it I noticed I could make it smoother by lowering the idle to exactly 1000 rpm, but did not like to leave it there as it made the throttle snatch worse. Tried to get rid of it, but eventually I just lived with it.

Interestingly, my 2014 has a very smooth idle with very little variation. I have no control over the idle speed as that is set by the ECU and fly-by-wire throttle. Maybe they did a better job on the 3rd Gen fuel map at idle?

 

[lnewlf]

I also keep idle high [@ 1200] to lessen throttle snatch...even so the idle has a slight roll ...I like it -reminds me of my small block Dodge with a high lift cam almost.. You should have an instant roll on surge with no lay down...if not mix might be off for any number of reasons..

 

[RossKean]

The only issue I have with it is that it is DIFFERENT from my (extensive) experience with my older Gen II. I was thinking it might be a symptom of something that may need to be fixed or adjusted. Perhaps I'll try to do a short video.

 

[ERS]

My 2006 with 90,000 km has the same loopy idle, I have put in new plugs and SeaFoam through it with no change. Idle is set to 1100 rpm. FredW's comments make sense. It doesn't bother me or affect performance or fuel economy so I am happy to live with it.

If you solve it let us know.

 

[BkerChuck]

My '07 does this on a regular basis as well. Only things I have noted are;

Seems worse when fuel level is low or near empty.

Non ethanol fuels when available seem to have less of an issue.

My spark plugs are relatively new and clean. TBS is within spec and idle speed set at 1100 rpm. All TBS port caps have been replaced and are in good shape.Seafoam run on a regular basis, about every 4 or 5 tanks I use it. It bothers me somewhat but not enough to pursue any further. If you come up with a solution please let us know as it would be nice to eliminate it.

 

[dcarver]

My 06 does the same thing, but not all the time. Some days idle rock steady. Other days, almost 100 rpm or more swing. I gave up.

 

[its just rain]

Hi Ross...My previous bike was an '11. I've said it several times, it ran better than my now '14. I don't think your current issue is normal, somethings not right.

 

[RossKean]

Hi Ross...My previous bike was an '11. I've said it several times, it ran better than my now '14. I don't think your current issue is normal, somethings not right.

Not sure that I would say there is something "wrong" - but perhaps not a "right" as it could be. Different than my '07 for sure and it may be something that can be changed but other than a mild annoyance to the rider (me), it has no effect on the operation of the bike. There is no surging at higher RPM or when riding at a steady throttle. I will work on it and report back if I find something. Until then, I would welcome suggestions of things to try when I get to it. I am not going to do anything major until the next time I am doing something under the tank.

 

[Niehart]

Ross, my 2010 does that also.

Red Neck Jay fixed his 2010 by adding a power commander of some sort and dyno time. It's now smooth as glass but it was not cheap to get the bike to that tune.

 

[RossKean]

Here it is. Odd how the dimmed LEDs flash! (Nature of the modulation, I guess)

Anyway, have a listen. Sometimes a bit worse than this. Warmed it up before I started recording.

 

[rbentnail]

My '07 has done this since day one regardless of idle setting. Never have found a way to get rid of it.

 

[RossKean]

My '07 has done this since day one regardless of idle setting. Never have found a way to get rid of it.

No where close to this extent with my '07. An annoyance, perhaps, with this bike and I will take reasonable measures to see if I can reduce or eliminate the lope but won't be devastated if I can't change it. (I wonder if richening up the idle using the Barbarian Jumper Mod would do anything?? Nobody has talked about that around here lately!!) Listening to the video in Post #11, I would say it sometimes gets a little more pronounced than that when stopped in traffic, but it may just be my perception sitting on the bike and with earplugs - hearing frequency response shift.

 

[mech 1 twa]

That's not right. Could be an o2 sensor problem. Try unplugging it . switching lean to rich. Check engine will be on but if it stops surging???? Not a TPS issue like any I had.

 

[Fred W]

So, thats a little more regular than the idle instability Im used to. Typically it doesnt cycle that quickly, when you have the lean stumble, though it does usually vary about the same amount. I guess you should go through all the usual suspects first. Plugs, sync, etc.

I tried to up my CO setting to reduce my lean stumble and was not successful, but mine was not so regular or cyclical.

 

[RossKean]

That's not right. Could be an o2 sensor problem. Try unplugging it . switching lean to rich. Check engine will be on but if it stops surging???? Not a TPS issue like any I had.

Didn't really think it was the TPS - far to repeatable for that.

O2 sensor is certainly a possibility. If unhooked or a wire is broken, that's easy to see. Is there any easy way to test? I had an O2 sensor issue on the '07 but in that case a wire was pinched under the timing cover (my fault, mostly) and it ran like a pig.

Guess I'll start with that, check for vacuum leaks and redo the throttle body sync. The bike had been pretty much unused for the past couple of years but I've put almost 4000 miles on it in the last couple weeks so it is unlikely a residual problem from old fuel. Hasn't really changed at all since the first tank. I think it pretty much has to be something fairly simple...

I'll probably get under the tank this weekend and see if there is anything obvious. Doesn't seem to affect driveability, doesn't surge at higher RPM, lots of power and fuel economy is about where I would expect.

Something I didn't mention - at cold startup it idles normally (at ~1500 RPM IIRC) without the lope. As soon as idle speed drops to 1000 RPM, it starts. Doesn't change behavior at idle anytime between a couple of bars of temperature right up to where the fans cut in.

 

[RossKean]

So, thats a little more regular than the idle instability Im used to. Typically it doesnt cycle that quickly, when you have the lean stumble, though it does usually vary about the same amount. I guess you should go through all the usual suspects first. Plugs, sync, etc.
I tried to up my CO setting to reduce my lean stumble and was not successful, but mine was not so regular or cyclical.

The Barbarian mod might or might not improve things but it would only be masking it, not dealing with a root cause. This being quite regular and higher frequency (in terms of periodicity), leads me to believe it isn't the usual FJR idle variability (that's why I mentioned a ~2 Hz (estimated, not measured) frequency).

Previous owner did the "Unauthorized" TBS before he stopped riding it. His other work on the bike has been meticulous so I have no reason to expect any issue. He also mentioned that, as far as he could recall, it always had some idle lope. In any case, it has sat long enough that it should be checked. I think I will lightly seat the four screws and start with them all out 3/4 of a turn or so...

Plugs are apparently new iridiums but, to be honest, I've used both the iridiums and conventional and don't find any noticeable difference. Might have been my imagination, but I got the impression that the '07 started easier with conventional plugs. Conventional plugs get changed at more than double the Yamaha recommended service interval.

Although it might take me longer, I will do this one step at a time. I would like to know the root cause!

 

[user 89595]

I am not an expert, but that kinda sounds like a vacuum issue. I sorta remember that sound when working old car engines years ago.

 

[mech 1 twa]

No way to test o2 sensor. If it has a long term lean -rich problem it should set a code. No signal , Stuck to upper or lower limit will set a o2 code. Lean- Rich or open circuit.