2007 rough, slow cold idle

worldbound4now · Jun 3, 2009

I own an 05 and am working on a buddies 2007 FJR. His bike starts really rough and the cold start idle speed is way too low (hovers around 500-700RPM with engine clunking and occasional stall). When the engine is warm it purrs like a kitten at idle. When cold and I hold the throttle open to maintain 1500rpm, the bike runs well.

A TBS was performed without improvement (didn't figure it would help).

His idle speed adjustment screw is turned all the way up. When I turn it down, the warm idle speed is affected similar to my 05 but the bike will absolutely stall when cold if I turn down the idle adjustment screw down.

I have the shop manual for his bike and haven't found any leads.

He has not modified the intake or exhaust from stock. The ECU recall was completed. He had a dealer attempt a TBS on his bike and reported rough idle before and after their TBS.

What activates the high idle on the 07? Shouldn't the mechanism that activates the high idle on cold start override any setting from the idle adjustment screw?

My plan.....

Check plug wires for firm connection.

Recheck all vacuum caps are firmly placed and in good shape without perforations (though this would affect the idle at more than just a cold start).

Look for other vacuum leaks or plugged/pinched lines.

Pull his air filter and see how dirty it is.

Check the O2 sensor wire.

Lookup how to pull error codes and see what is displayed (I can do it on my 05. Is the same on the 07?).

Any other suggestions?

Thank you!

Worldbound4now

RadioHowie · Jun 3, 2009

I read it all twice to make sure I didn't miss something. I didn't. You didn't say it so I'll ask it.

What's the idle speed when the bike's completely warmed up?

And I do mean completely....not "when it's showing XXX bars on the temp". Drive 2 or 3 miles, park it and read the idle speed. What is it?

PA1195 · Jun 4, 2009

It sounds like your cold-start air bypass system isn't working. Look on the lower left of each throttle body and you will see individual air-bypass valves that are pulled open by a common sliding rail just below the throttle bodies when the bike is first started. How that is enabled will be apparent. Make it work back and forth if you can without breaking it.

I don't recall the exact switch/enabler, but if you look closely you will see it at the left end of the rail where it moves the rail to the left to open the air valves. I think that's right and it's called the Plunger Valve assembly in the SM under the Throttle body removal instructions. At initial start-up, the ECU calls for additional fuel, and I believe that requires additional air to be bypassed around the closed throttle plates to create a higher idle rpm until the engine is warm. Opening the bypass valves does just that, otherwise, the bike will run rough due to too rich of an initial mixture, and require opening of the throttle plates via the idle adjustment screw.

My '08 SM doesn't address it's operation, or at least I couldn't find it described. Look and you'll see what I'm talking about. It's some vacuum (and maybe electrical) driven gizmo likely controlled by the ECU. Not even called out via P/N in the Yamaha parts fiche as far as I can tell. Fix it and your problem may be solved. Just compare it's operation to your '05 to see if it's really the problem, and not something else. Weird deal that it's not explained much. Cheap beers will do that.

Gary in Fairbanks

worldbound4now · Jun 4, 2009

I just finished a 12 hour shift and have another tomorrow. I'll try to check things out more over the next day or two. Thank you PA for the suggestions.

This bike has had several other maintenance items addressed (all chassis related) that have not allowed me to run the bike up and down the street yet. Hopefully I can do that tomorrow or Friday and find out what a hot engine idle is.

Keep up the suggestions!

worldbound4now · Jun 4, 2009

PA1195 said:
It sounds like your cold-start air bypass system isn't working. Look on the lower left of each throttle body and you will see individual air-bypass valves that are pulled open by a common sliding rail just below the throttle bodies when the bike is first started. How that is enabled will be apparent. Make it work back and forth if you can without breaking it.

I found the sliding rail and moved it back and forth a few times, started the bike cold, and had the same rough cold idle. When holding the bar to the left, I was able to get the bike to do a clean smooth idle.

Rethinking the TBS, the procedure involved me watching the meter while the bike owner adjusted the #1 and #2 screws at my instruction. I recall him expressing difficulty with the #1 screw at about the point that we had great balance in vacuum, so I told him to leave it as it was.

I found the #1 adjustment screw bottomed out and the #2 only open about 1/8th of a turn. I turned them all (including the holy grail don't touch #3 screw) out one full turn and resynched the throttle bodies. On restart from one full turn out the idle speed was much faster but rough. With the meter connected, I rebalanced the TBs while turning down the idle speed adjustment screw as needed to return to 1000 rpm. The idle speed adjustment screw is now no where near it's maximum setting, the hot idle is smooth as can be, and the bike is sitting in the garage cooling off to see if the cold engine high idle will work again. Hopefully this all spawned from a boneheaded move of allowing the throttle body adjustment screws to bottom out and cut off vacuum to what may be used to run a diaphragm device for the cold start high idle.

Moral of the story, never be satisfied with any setting that is near a maximum or minimum limit. Something is wrong even if the bike runs well.

worldbound4now

PA1195 · Jun 4, 2009

Good deal, now we're getting somewhere on how the cold-start setup works - the SM doesn't address it as far as I can tell. I'm riding today, but I need to raise my tank soon on my '08 and look at the setup again, and do the initial TBS. It's been a few years since I did my last TBS on the former '07 I had. Try and see what source (vacuum?) and temp or ECU controlled switch (location?) activates the slide rail. Must be temp activated valve of some sort that controls the vacuum in the lines until the engine warms a bit. That's all gotta' work right. I wish I had mine exposed so I could figure it out better for the thread. Maybe someone else can offer some help as I'm no expert.

As far as the TBS, the idle air bypass screws we adjust can be set to match at about 1/2-3/4 out initially. The 250mm Hg that Yamaha specs for #3 assumes near sea level pressure, and may not be achievable at higher altitudes even with the idle screw bottomed out. I assume it's just a guideline, and I would not initially close the screw any more than 1/4 turn from bottom trying to raise the value of #3 to 250 mmHg. Then just set the rest at 1100 rpms to match. Later do the throttle plate adjustment at cruise rpms if desired.

Let us know what fixes it for good.

Gary in Fairbanks

worldbound4now · Jun 6, 2009

Problem fixed by opening TB adjustment screw on cylinder #3 one full turn then redoing the TBS to balance out with #3. This set all four adjustment screws partially open, unlike the previously mentioned setting where #1 was completely closed. Bike owner made it back to his home (4 states away) without mechanical incident and the feeling of a new FJR (TBS, removed throttle slack, coolant flush, brake/clutch fluid flush, new tires, front fork rebuild, steering bearings repacked, levers/linkage lubed, yadda yadda yadda).

worldbound4now

beacher · Jun 7, 2009

Glad that you said something about that "clunking" sound, because mine will do that a couple of times when it's been sitting overnight; the first time it did it, I was afraid that it was going to snap into gear and run off the stand. It still makes me a little uncomfortable when it happens, but it's been doing it ever since I bought it, so I've "kinda" gotten used to it. . .

Metric · Jun 9, 2009

Glad I found this thread! I was just considering messing with #3 TB for almost the same reasons. My idle adjustment screw is all the way in also with the idle set at 1000rpm. Although, most of the time the bike is fine, there is a real specific time as the high idle drops off when the bike is warming in the morning that the RPM's get to low and the motor clunks along like you described. I'd like to bump up the idle speed to about 1100 as I believe the ol' girl will be a bit happier there. Interestingly, the transition issues from high idle showed up right after the ECU recall happened.

worldbound4now · Jun 9, 2009

Ok, so my buddy returned to his home and reports the issue remains present, though intermittent. Hmm..... I keep wondering about the ECU myself. I encouraged him to go to a reputable Yamaha mechanic instead of this shadetree mechanic to evaluate his steed. Something is wrong and should not be accepted as normal. Oddly, his high idle was never as high as mine on my 05. I could make it go as high as mine by moving the bar at the base of the throttle bodies left as mentioned in post #3, but the bike did not want to do this unassisted. Grrr.... It frustrates me even though the bike is now several states away.

Metric · Jun 10, 2009

Frustrates me also! I went through the bike a week ago, installed new plugs, TB sync, air filter, checked all the vacuum lines for issues. Got it running like a champ in the garage, thought I had it fixed. Rode it to work the next morning and just as I was leaving the neighborhood I was back to square one. About a half mile from my house is a stop sign. If I start the bike and let it run long enough to put my helmet and gloves on, then pull out of the drive and go that half mile, I hit that stop sign just as the bike is coming off high idle (2 bars on the temp gauge). That is where this always happens. Push through its little tantrum and a mile later its usually fine (at least it is now that I did the tune up, it might have acted out on occasion before that). Until I able to redo the TB sync though, I feel that the overall idle needs to be adjust up just a little more then I can get it right now.....give me a couple of days to make time and I'll report back and tell you if my feeling is right.

twistedcricket · Jun 10, 2009

The bike from post #1 is mine. It was idling 'rough' and low prior to the visit. After the TBS (2nd, probably) and some tinkering WB4N was happier with it. It didn't have a super rough start when I fired it up to return home.

I let it sit from Saturday afternoon to Monday morning. That Monday morning start was really rough. Sub-1000rpms, I revved it gently twice and it seemed to settle in to a purr at 1000. I didn't have any further problems getting to work (several stoplights, or chances to sit and idle) With 60% rain chances the last two days it's been in the garage again.

Plugs were changed to NGK iridiums in March. All of this other work has been done in the last two weeks.

I don't have a way to do a TBS at home. It's "only" a 12hr ride back to the good garage. Taking it to a dealer requires a 60 mile trek and my schedule is full this week.

twistedcricket · Jun 10, 2009

Metric said:
Frustrates me also! I went through the bike a week ago, installed new plugs, TB sync, air filter, checked all the vacuum lines for issues. Got it running like a champ in the garage, thought I had it fixed. Rode it to work the next morning and just as I was leaving the neighborhood I was back to square one. About a half mile from my house is a stop sign. If I start the bike and let it run long enough to put my helmet and gloves on, then pull out of the drive and go that half mile, I hit that stop sign just as the bike is coming off high idle (2 bars on the temp gauge). That is where this always happens. Push through its little tantrum and a mile later its usually fine (at least it is now that I did the tune up, it might have acted out on occasion before that). Until I able to redo the TB sync though, I feel that the overall idle needs to be adjust up just a little more then I can get it right now.....give me a couple of days to make time and I'll report back and tell you if my feeling is right.

Metric what year is your bike? I'm guessing Gen II but it's not listed in your profile. Since you're a little closer to me than WB4N, could we work together and figure this out? I'm more than willing to cruise down if the schedules would work out. I don't have a carbtune/mototune or any other such device for a TBS (although after seeing the procedure, I should get one).

Metric · Jun 10, 2009

twistedcricket said:
Metric said:

Frustrates me also! I went through the bike a week ago, installed new plugs, TB sync, air filter, checked all the vacuum lines for issues. Got it running like a champ in the garage, thought I had it fixed. Rode it to work the next morning and just as I was leaving the neighborhood I was back to square one. About a half mile from my house is a stop sign. If I start the bike and let it run long enough to put my helmet and gloves on, then pull out of the drive and go that half mile, I hit that stop sign just as the bike is coming off high idle (2 bars on the temp gauge). That is where this always happens. Push through its little tantrum and a mile later its usually fine (at least it is now that I did the tune up, it might have acted out on occasion before that). Until I able to redo the TB sync though, I feel that the overall idle needs to be adjust up just a little more then I can get it right now.....give me a couple of days to make time and I'll report back and tell you if my feeling is right.

Click to expand...

Metric what year is your bike? I'm guessing Gen II but it's not listed in your profile. Since you're a little closer to me than WB4N, could we work together and figure this out? I'm more than willing to cruise down if the schedules would work out. I don't have a carbtune/mototune or any other such device for a TBS (although after seeing the procedure, I should get one).

My bike is an '06. Currently showing just short of 30K on the odometer.

I would love to help you out, but I would like to make sure I am able to get mine running right before I start tinkering with someone elses bike. I would be much more comfortable working on yours if I know what it took to get mine right.

twistedcricket · Jun 10, 2009

Metric said:
My bike is an '06. Currently showing just short of 30K on the odometer.
I would love to help you out, but I would like to make sure I am able to get mine running right before I start tinkering with someone elses bike. I would be much more comfortable working on yours if I know what it took to get mine right.

We could compare notes in the meantime. I have a full fuel tank, so I'd rather burn a little of that off before lifting that heavy beast. WB4N mentioned that he last tuned the idle speed when it wasn't bent to it's standard position. It seems to be a little bound up at the moment and it wouldn't turn easily when I attempted to adjust it. I might try to lube that with some lithium soap or something.

dbx · Jun 10, 2009

Metric,

I'm in Olathe, probably about 15 minutes away from you, in case you want another set of eyes or hands when you go to work on it. Just let me know.

Metric · Jun 10, 2009

dbx said:
Metric,I'm in Olathe, probably about 15 minutes away from you, in case you want another set of eyes or hands when you go to work on it. Just let me know.

Thanks! I'll keep that in mind. Can't have to many brains trying to figure out a weird problem.

twistedcricket · Jun 11, 2009

Link to a thread discussing a similar issue

I haven't tried the barbarian mod yet... not sure if it's worth a shot???

Metric · Jun 11, 2009

twistedcricket said:
Link to a thread discussing a similar issue
I haven't tried the barbarian mod yet... not sure if it's worth a shot???

I have tried it with factory settings all the way up to +10 on each cylinder.....no dice. I have had my CO settings turned up since shortly after I got the bike. The only reason I went back to the factory settings was because I felt like I had done everything else. I actually went back to the factory settings just before I posted on this thread. It doesn't make a difference on my bike weather the settings are factory or + whatever. I think maybe this weekend I'm going to go after the holy number 3 throttle body screw. The first thing I need to be able to do is adjust my idle up higher. I think my bike will be fine if it would just idle 100 rpm higher then it is now. Every since I did the TB sync, the only time I have issues is right as the ECU turns off the high idle when it starts to get some engine temp.

2007 rough, slow cold idle

Help Support Yamaha FJR Motorcycle Forum:

Well-known member

I Miss Beemerdons&#33;

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

You have whiskey?

You have whiskey?

Well-known member

You have whiskey?

Well-known member

Well-known member

You have whiskey?

Well-known member

Similar threads

Join the conversation!

Join today and get all the highlights of this community direct to your inbox. It's FREE!

I Miss Beemerdons!