[wgharper]

Hi all,

Been doing some searching and it seems like this issue may have been experienced by others, but I figure it might be good to get some fresh perspective since the other threads were a few years old (and none really had definitive answers or solutions).

Background:

• 2007 A model, 10k miles (just bought last weekend, took delivery yesterday)
• Recently brought back into service after 10 years in a garage
• Shop recently cleared the old fuel, put in new fuel cap, fuel pump, and injectors (so some recent work in intake area)

Symptoms:

• Cold starts fine, 1300ish RPMs until warmed up
• Once warmed up, idle quickly drops to 500-700 and stalls
• Seems to get worse once fully warmed up (after a short ride)
• Bike runs great when not idling from what I can tell, but just will not idle when warm

Tried so far:

• Warm idle adjustment screw was already clockwise to the max
• Noticed battery was nearly drained (it's new in the past year). Put it on a trickle charger overnight on the off chance it's voltage-related.
• Lots of searching in preparation for digging in

From the collective wisdom of those of you who may have seen and solved this in the past, what should I be focused on for diagnostics first? Going to start with TPS test, pulling the air filter to make sure it's not gummed up, and unplugging and reseating the plug for the ECU.

 

[jaroslawjaroslaw1234]

Hi. I'm thinking of a few things. Check the intake pressure sensor. Check compression on a warm engine. Check valve clearances. Check the cylinder liners with an endoscope camera - they may be cracked (nicasil).

 

[fjrlee]

I had this problem after checking and cleaning everything suggested in other posts.

In my case the exhaust valve timing was out by 1 tooth. The bike starts and appears to go fine but will not idle. There is also some loss of response above 6k. This has happened to other people too.

Were the valve clearances adjusted in the past ??

 

[rbentnail]

I had this problem after checking and cleaning everything suggested in other posts.

In my case the exhaust valve timing was out by 1 tooth. The bike starts and appears to go fine but will not idle. There is also some loss of response above 6k. This has happened to other people too.

Were the valve clearances adjusted in the past ??

This. Classic symptoms.

 

[RaYzerman]

Before diving deep into valve timing..... I assume at 10k nobody fooled with it (i.e., replaced the CCT and inadvertently got the timing off).........
If you've run out of idle adjustment, very good chance the throttle body sync screws may have been altered, which can reduce your idle range. Start by turning in every sync screw until lightly seated, making note the amount of turn on each one. Then back them all out 3/4 turn. Using one as a reference (it was usually #3 on a Gen1/2), do a sync to the reference cylinder. OR, just fire the bike up as is and see what your idle is without a true sync (but you will sync eventually).

My guess is a couple of screws are in too far thus starving for vacuum at idle..... see what the above fix does for you. If you wish to tweak further, move your reference screw out another 1/8-1/4 turn, then re-sync.

Give it a shot, I think it's likely that simple.

At 10k, the MAP sensor (intake air pressure) vac nipple and hose is not likely clogged with gunk, but, while you're in there, check anyway. Two screws to remove it.

 

[wgharper]

Thanks @frjlee and @RaYzerman. I'll check the TB sync first and hope that's the issue, but add the valve timing check to the list in case that doesn't pan out.

@RaYzerman - are you suggesting that I change the reference cylinder's screw as well when I do the initial reset you describe above? Or just that I do that with 1,2 & 4?

 

[FastPappy]

May sound silly but even before you go that deep I would check the adjustment on the cables not just the idle screw. Remove all play first then recheck idle screw. Just my 2cents.

 

[wgharper]

I think I found the answer to my above question about reference cylinder from @RaYzerman in a 7 year old thread:

Bernie is correct on Gen3, use of the cylinder with the least air flow, as is the approach on Throttle By Wire. All prior Gens state #3 in the FSM. However, that is different in that you start with some value of air flow, and as long as they are all the same, you're good. The value is not important. Sometimes #3 was not set by Yamaha far enough out and you may not be able to get a good sync.... thus, default to the FSM section where they say set the screws (initially) to 3/4 turn out (I have found a little more than 3/4 and less than 1 turn is better. The reason I don't go more than 1 turn is the springs on the screw shafts that serve to keep them in place can get a bit too loose for my liking. Then you can pick any as a reference and sync to that. Stick with #3 if you like, no issue. Sync just means that.... all are sync'ed to be the same.

Link to the thread for reference. Internet is amazing.

 

[RaYzerman]

Gen1/2 - Screw them all in and make notes.... screw them all out 3/4 and note the vacuum readings with sync tool attached. It doesn't matter which one is the reference, as long as it remains 3/4 turn out and you can get the others synced uniformly to the reference. This should get your idle range such that you have adequate adjustment on the idle screw..... final sync with idle at 1000-1100 rpm.

Gen3 a different story in that one screw will be turned in all the way and becomes reference.

 

[wgharper]

Quick update...

I tore into the bike last night to try to get this resolved. Seeing improvement but not quite there:

• Confirmed air filter is clean and relatively new
• Followed RaYzerman's guidance on resetting the TBS screws

Initially this did not help much - but it did allow the bike to continue running at low (600) RPM instead of stalling. I then set out to check vacuum hoses, and while giving each a tug/twist, the idle popped back up to around 1050 rpm and held steady. At that point it started to rain so I didn't get to do the TBS procedure, but this seems promising. I think I'll go ahead and block off the emissions-related tubes and remove and clear all the vac lines to see if that helps. The warm idle screw is fully in, so I think there's still some progress I can make to increase warm idle further. Anyways, progress is good, so thanks and I'll continue to post updates as I learn more!

 

[wgharper]

Another update. Finally got to do the TBS procedure. Nothing wildly out of sync, got it dialed in. Bike is still idling at about 1050 for a bit then something happens and it stalls out. I’ll also note that when the rpm’s drop to 500-600, the vacuum in the throttle bodies spiked on my meter (all four pins hit the top of the case repeatedly as it ran). Not sure if that’s helpful diagnostic info or not.

side note - getting the rubber nipples off is a nightmare. Period. Full stop.

 

[jasonm.]

when vacuum goes up on sync tool means a vacuum LEAK may been solved somehow. You said w]hoses wiggled and idle improved. I am thinking vacuum hose. But the idle screw should never be fully CW to the end. When I resolved the my injector issue, Ray helped me a while back with my idle doing same procedure, and it became a rocket from any speed. I run 5th down to 2500 on back roads and gradually get it to 3000 because its a beast beyond 3000. Yet 44mpgs are easy because of the constant torque. Just hoping yours is not a timing issue

 

[RaYzerman]

Correct the idle screw should not have to be fully turned in.......

Interesting you didn't get the result I was expecting...... did you happen to check/clean the vacuum nipple and hose on the MAP sensor? I am curious which vacuum hose you were tugging on to get the idle to 1050.... MAP sensor hose?

Would also like to know if there is a green or blue paint dot on the cam chain tensioner (CCT). If so, it means someone changed it to the new one, and we can only hope the cam timing was preserved. However, there's another test for that before diving in too deep. It's only got 10k, so I'm thinking no one would think to change the CCT just yet.

 

[Sleuth]

I hesitate to add my two cents because my engine knowledge is close to zero. But here goes.

About two years ago I bought a 2014 FJR from a neighbor with 2,500 original miles on it. I also had the problem of the engine stalling when it was fully warm if I coasted with the clutch pulled in or stopped in neutral. In all other respects the bike worked fine.

After scratching our heads for a while we decided to put in new spark plugs. (Probably because that was one of the few things we knew how to do.) For whatever reason that fixed the problem completely and 7,500 miles later it hasn't come back.

With only 10k on your bike, it's possible you still have the original spark plugs. If so, you might try replacing them.

 

[jasonm.]

At normalish idle could possibly be electrical ignition wires because the total potential electrical energy may be less, but with respect to that I would look at the "CAPS" they are rebuildable by disassembly with a QUALITY straight screw driver. NO need to replace. Be careful when disassembling, there's a spring, resistor and brass plug. They can get carbon deposits inside if there is internal arcing. 2000 paper cleans most all items at their ends perfectly in seconds. But the area that often get carbon is where it all rests at the end on the cap closest to the wire. This requires patience to clean. A brass rod approx. 1/8"w and not perfectly smooth at the end, that fits and rotating it while pushing, gets carbon loosened. Some people spin carefully the spring to do same. But that's steel on brass and requires needle pliers. That's why I use brass 1/8" rod. Use a good flashlight to look in. It will go from dull to shining bright down there. Disassembly can be done carefully with wire attached. If you remove the caps remember the wires have only 1/2" or so of spare length. If you cut them back , you may with to carefully take the insulation off & leaving the copper core strands sticking out. Then spread the copper strands before threading cap back on .

 

[wgharper]

Correct the idle screw should not have to be fully turned in.......

Interesting you didn't get the result I was expecting...... did you happen to check/clean the vacuum nipple and hose on the MAP sensor? I am curious which vacuum hose you were tugging on to get the idle to 1050.... MAP sensor hose?

Would also like to know if there is a green or blue paint dot on the cam chain tensioner (CCT). If so, it means someone changed it to the new one, and we can only hope the cam timing was preserved. However, there's another test for that before diving in too deep. It's only got 10k, so I'm thinking no one would think to change the CCT just yet.

I wish i could say which vac line I moved to cause the idle to stabilize but it wasn't a precision exercise and they are all linked, so it could have been any of them. I did pull the MAP sensor and checked the nipple, which was clear. Going to just pull all the vac hoses this weekend and give them a thorough clearing I think. I'll also get a mirror out and check the CCT. It's odd that I'll actually be rooting for it NOT to have been done, just to rule that out from this issue LOL.

@Sleuth I agree I probably should at least pull the plugs and check the gaps and condition. Actually may just replace since they're relatively cheap. @jasonm. I'll check the wires while I'm in there too. I also saw one thread where a similar issue wound up being fixed by replacing a non-Yamaha battery with a fresh Yamaha battery, so certainly could be electrical/ignition.

 

[RaYzerman]

Jason's suggestion good too, may be low mileage, but it's been sitting a lot..... once you have the spark plug caps off the wires, check the resistance, should be ~10k ohms. If significantly less, it means corrosion as he mentions and cleaning it up should restore the correct resistance.

I'm gonna guess your vac lines are clear..... wiggling MAY have meant you temporarily induced a vacuum leak, thus idle increased until it sealed again.... note the vac caps for the sync tend to rot and crack.... get some better ones at the auto store (no need for the metal clips).

No need for a mirror on the CCT, once you have the tank up and insulation pad off, just look down on it....... dot should be on top mounting flange. New on the left, old on the right.

 

[skippy344!]

I am battling this same issue currently... Mine is a 2006 with 41k miles.

I sent my injectors out for service, and just got them back. They were a little dirty, but all were performing as required. New screens and flow test is bangin'!

I replaced all of the hoses on my TB. They are all tight against their respective nipples now. They were "slidey" before...

Cold idle and it is perfect! Best running bike I ever had. After it gets warm...stumbles, misses, and often stalls upon decel or at a light.

We cannot but a new wax valve for the cold idle. It does not have a part number on the exploded diagrams. That is where I am gonna look next, if the clean injectors don't fix my issue.

 

[wgharper]

I am battling this same issue currently... Mine is a 2006 with 41k miles.

I sent my injectors out for service, and just got them back. They were a little dirty, but all were performing as required. New screens and flow test is bangin'!

I replaced all of the hoses on my TB. They are all tight against their respective nipples now. They were "slidey" before...

Cold idle and it is perfect! Best running bike I ever had. After it gets warm...stumbles, misses, and often stalls upon decel or at a light.

We cannot but a new wax valve for the cold idle. It does not have a part number on the exploded diagrams. That is where I am gonna look next, if the clean injectors don't fix my issue.

Hey @skippy344! I've been watching that thread too. FWIW, my bike has new fuel pump, fuel cap, and injectors, all of which weren't up-to-spec after the bike came out of a 10 year hybernation. So we have that in common - new injectors not solving the warm idle issues. Hoping I can find a fix and that it helps you and maybe others.

 

[skippy344!]

I have also replaced the fuel pump, had a meter on it to see if the pressure was good. It is.

I am really wondering if it is that cold idle wax valve... We will see.

And, also if I fix mine, I will report back.

It is so weird that so many of this gen are showing this symptom..