FJRiders.com

Posted "over there" a little while ago. Thought I would see if anybody here had some insight...
(not a contest - just tried there first!)

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 (one split - replacing made slight improvement maybe)
Look for other possible vacuum leaks (using propane or starting fluid) (Nothing apparent)
Redo TBS (Pretty close but I tweaked it a bit)
More Ringfree or Seafoam (couple of tanks with Seafoam - no difference)
Check plug wires and seating of connectors (Nothing obvious)
Check that O2 sensor is connected (It is)
Conventional spark plugs? (Haven't tried yet)
Ignore it and buy better earplugs?

Other thoughts?
Throttle position sensor correctly adjusted?
Bad O2 sensor - any way to test?
Try conventional plugs?
Possible issue with one or more injectors? I would expect issues with driveability, power and fuel consumption if an injector was significantly plugged - worse at wider throttle openings.


Edit:
Previous owner played around with Barbarian jumper mod a bit but said he only went to +3 for all cylinders. I think he said he set them back - I haven't checked.
He also mentioned that he had an issue with one fuel injector - clogged due to bad fuel. He had all four professionally cleaned and tested.
Bike was idle for most of two years before I bought it. Stored with stabilized fuel. I have put close to 4000 miles on it since then so no residual old gas in tank.

It just runs too darn good at higher RPM for it to be anything really bad but the idle is annoying - especially since the '07 didn't do it at all.

This is a YouTube video of the idle variability:

I think it is likely normal to have some minor up and down surging at idle, my Gen3 has it too at times. If it's minor, ignore it, no harm is being done. Changing plugs won't help, no way to test the O2 sensor (hard to believe it is bad anyway), injectors were already cleaned but running Seafoam some more won't hurt either....
Probably not a valid comparison to the '07, that generation of FI software was a different animal... '08 was changed, perhaps even '09, to correct some of the issues '06/'07 had.

Doesn't sound normal to me...I've had three FJRs.

raYzerman wrote: ↑Thu Jun 14, 2018 12:26 am I think it is likely normal to have some minor up and down surging at idle, my Gen3 has it too at times. If it's minor, ignore it, no harm is being done. Changing plugs won't help, no way to test the O2 sensor (hard to believe it is bad anyway), injectors were already cleaned but running Seafoam some more won't hurt either....
Probably not a valid comparison to the '07, that generation of FI software was a different animal... '08 was changed, perhaps even '09, to correct some of the issues '06/'07 had.

This is, perhaps, more pronounced "in person". It is present all of the time once the bike is warmed up, but only at idle. As I mentioned, there are no problems with other aspects of the bike's operation. I understand that fuelling changes were made in Gen II's between the time of my '07 and the '11 but I haven't heard this sort of thing before - at least not to this extent. Previous owner mentioned he had noticed some variability but not as much as I am experiencing with this. (He had a listen to the video.)

Ride More. Worry Less.

I have this on my 07, had it fixed once by spending a LONG time with the synching process, then stupidly tried to set the Synch at 4000 rpm to help with handlebar vibration and now it "lopes" again. SIGH

Okay okay, I'll play. Swap out the aftermarket cans for stock pipes. I think your experiencing back pressure resonance up through the intake tract (affecting scavenging).

philharmonic wrote: ↑Thu Jun 14, 2018 7:53 am I have this on my 07, had it fixed once by spending a LONG time with the synching process, then stupidly tried to set the Synch at 4000 rpm to help with handlebar vibration and now it "lopes" again. SIGH

Previous owner did the "unauthorized" synch procedure - I wonder if that got messed up somehow. When I did the TBS, it was not off very much and setting it dead on didn't improve things. The high(er) throttle response shouldn't be relevant at idle although maybe there is some strange combination of throttle plate position and idle setting that is causing this issue. I have no idea how to undo a throttle plate adjustment back to stock to see if that could be a problem. (He did a lot of work on this bike himself and, so far, I don't see evidence of mechanical incompetence.) Is your idle variability as much as mine?

bungie4 wrote: ↑Thu Jun 14, 2018 8:42 am Okay okay, I'll play. Swap out the aftermarket cans for stock pipes. I think your experiencing back pressure resonance up through the intake tract (affecting scavenging).

I was wondering if that might have been a factor. I have the "quiet" baffles in which would increase backpressure to some extent and actually used a rag to partially block one of the mufflers for several seconds. Again, this would serve to increase backpressure. Essentially no difference in idle "lope". The Staintunes are not especially noted for being a particularly aggressive pipe anyway.

Idle speed that wanders 100 - 200 rpm is within a range of normal for motorcycles.

Motorcycle engines are tuned for high HP from low displacement engines which is part of why motorcycle engines have high idle speeds compared to cars, they can't idle at lower RPMs. Additionally, motorcycle engines have low reciprocating mass and low flywheel mass which contribute to wandering idle speed. Put some additional flywheel weight on the engine and the idle speed won't be nearly as sensitive -- but -- the engine won't accelerate as quickly because of the extra mass. It's a balancing act. Typically, 4 valve engines are at their best at large throttle openings, induction at low throttle openings is not optimum and is very sensitive to vacuum levels. Aftermarket cans can lead to excessive cylinder scavenging at idle and contribute to wandering idle. Because the idle tuning is right on the edge it is not surprising that some bikes will idle smoothly and other will slightly wander.

My '04 was a wanderer. I bumped the CO then wandering and surging got better, but over all I didn't like the engine feel and driveability. I added a Power Commander and that made a difference to idle stability. When I do a TBS I continually adjust the RPM to 1,100 during the sync. I tweak the sync screw and adjust the RPM back to 1,100 and continue the sync and adjust the RPM as needed. This helps give a smooth idle speed and prevents the idle adjustment screw from either bottoming out or topping out at the end of the sync. My '15 sounds like there is an idle wander but the tach needle is dead stable. I dunno if Yamaha messed with the tach signal so that it shows steady idle speed or if the ECU makes continuous adjustments (ding, ding, ding) so that the tach is stable but the fueling is always being tweaked which causes the sound of wandering but keeps the tach needle stable.

It's good to always pay attention to the little things, but it is also good to keep straight the difference between something casually noticed vs something that's not normal in a more serious way.

Is your idle stable when the engine is cold? If yes, it implies two things, higher rpm is good but more importantly, the engine is in the fuel enrichment routine and is running rich.

If the idle is stable when cold but not when it's hot then there are two things to focus on, one is vacuum level and the other is engine fuel leanness. High vacuum will always produce a smoother idle speed; high vacuum = high intake port velocity which is desirable. Just as a troubleshooting step, if you can bump up the CO level by 10-12; does the idle smooth out? If yes the idle speed wander is most likely due to a slight lean condition. (Now, return the CO levels back to the previous setting.)

If it looks like leanness is likely to be the root cause you can have the fuel injectors cleaned and balanced. It may help but won't hurt, and it isn't a bank-breaker.

If it were me, I'd be very mildly annoyed and ignore the wandering as best as possible. Also, I'd advise to avoid as many situations as possible where you may have to idle, after all, you aren't going anyplace at idle

Just for shits and grins. Re-torque your exhaust bolts at the head. Won't cost nothing and a leak there can have the same affect as a vacuum leak on the intake side. Just because you don't hear the tell-tale popping doesn't mean their isn't an issue. Do the same at junction between the Staintunes and the header.

You do know, sometimes, like people and animals, engines are just assholes.

ionbeam wrote: ↑Thu Jun 14, 2018 9:21 am Idle speed that wanders 100 - 200 rpm is within a range of normal for motorcycles...

... If it were me, I'd be very mildly annoyed and ignore the wandering as best as possible. Also, I'd advise to avoid as many situations as possible where you may have to idle, after all, you aren't going anyplace at idle

Hard to tell the amount but I would say that the variability is probably not much more than 50-75 RPM based upon the needle wander but that might be a function of meter damping. Perhaps the frequency is the irritant? Its very regular and doesn't seem to change much with ambient temperature or anything else. Not sure if the lack of variability on cold start is a function of richness or engine speed. Might mess with Barbarian CO adjustments to see if it goes away with richening (at the same RPM). In any case, I will jump through at least a few hoops to get it fixed (but only if they are really big and low to the ground). Fuel injectors - thought about getting them serviced and may do so if I can find someone local who is competent and can turn them around quickly. While I could swap them out of my '07, I'm hoping to get it sold pretty soon and it probably isn't the best idea to "show" a bike with the tank lifted and vital parts missing - especially one with 185,000 miles that I am claiming has NO engine-related issues. (That one has an idle that has no discernible idle variability - haven't even done a TBS in 2 years - well before my last valve check and adjustment.)

I get the "avoid idling" thing but they frown on failing to stop at lights and in traffic. Guess I'm just riding in the wrong places lately!

bungie4 wrote: ↑Thu Jun 14, 2018 9:29 am Just for shits and grins. Re-torque your exhaust bolts at the head. Won't cost nothing and a leak there can have the same affect as a vacuum leak on the intake side. Just because you don't hear the tell-tale popping doesn't mean their isn't an issue. Do the same at junction between the Staintunes and the header.

You do know, sometimes, like people and animals, engines are just assholes.

Not a bad thought. It will have to wait until I have occasion to remove the lower fairing to do between the engine and header but I can check the junction to the Staintunes. It certainly doesn't sound like there is any exhaust leak but my hearing pretty much sucks in certain frequency ranges. (good with foghorns, not so much with mosquitoes)

If the CO settings were only changed by 3 and then set back, why mess with that. As for the unauthorized sync, you don't know where it's at. Best way is to remove the throttle bodies so you can physically see and measure (with drill rod) the amount the throttle plates are opening, and adjust precisely, it's the only way to do it properly anyway. Take all the sync screws out (don't lose anything!) and clean them and the passages. Seat #3 sync screw and back it out one full turn, then sync the rest. Sometimes #3 was never out far enough.

Thanks Ray. I don't think I am ready to pull the throttle bodies to accurately adjust the plates yet. Hoping that they aren't very far off! If they're totally messed up, that might be the only way to restore balance. If I redo the TBS starting with #3 out one turn and I can't achieve an appropriate idle with the idle adjustment screw, than I can probably assume that the throttle plates are too far open (or closed) compared to ideal. I wish I had an "absolute" vacuum gauge rather than a differential manometer - it would be nice to start with the #3 at the "right" vacuum level rather than the one-turn-out guess.

Might not be a bad idea to redo the TBS from scratch since I don't know where the #3 screw is at this point. Would the throttle bodies have to be removed to clean the passages? I was thinking about removing the vacuum caps and giving each port a shot of Seafoam "Deep Creep". Then back out the screws and give each another shot and allow to soak for a bit. Any crud in there is going to be organic hydrocarbon residue so wouldn't hurt anything if it made it into the engine.

I remember a thread that Jeff Ashe did that described his Seafoam engine treatment where he introduced a bunch of Seafoam through the vacuum ports while the engine was running. The object there was to get the stuff into the cylinders to burn off carbon deposits. It probably did a good job on the synch port passages at the same time.

I would rather squirt solvent down the holes the sync screws came out of, and clean the screw tapered ends at the same time. A carb cleaner won't hurt either. #3 screw 3/4-1 turn out is good enough, don't worry about an absolute value.

I have never had the airscrews out before. Is there any issue with losing bits. Can't really tell from the parts fiche but there is the screw, a spring and what may be a washer and o-ring??? I have no idea whether these all come out with the screw or if parts stay behind to be lost or solvent damaged when flooded with a cleaner.