Stalling Issues?

[rick]

Finally got my 1st ride of the season in today. The bike has been in a detached garage and not fired since somewhere in November. It lit up and ran like it was just started yesterday. FI is just awesome when it's right.
 
That said, I managed to stall it in traffic once pretty early into the ride. Dang near got rear ended as well. . The rest of the ride was spent concentrating on getting the revs up before letting the clutch out even a hair. This seemed to work. Of course, when I try to make it stall, it won't.
 
Gonna try and get gauges on it next weekend.

[SoCal1904]

after close to 3k miles on the bike I was riding home from work today and it stalled twice on me for no reason and for the first time since ive owned it. I seemed to be able to narrow down what I did and find out when/ why it was stalling.
 
So the first time it happened I was coming to a stop light and was downshifting from 4th to 1st and once in first I gave it a little throttle to rev the exhaust and boom it just cut out and died. Started back up with no problem and went on my way about 30mins down the freeway.
 
2nd time, 30 mins later, I (AGAIN) was downshifting from 4th to 1st coming up to a stop sign and once in 1st while still rolling and clutch pulled in, I gave it a little throttle to rev the exhaust and boom it died again and seconds later started up no problem.
 
I have the 2 bros exhaust and no ejk and in 1st gear if I give it a little rev it almost sounds like it cuts out a little and so thats where im at with the stalling issue.

[hippiebikerchick]

Do our two pistons fire at equal intervals? I vaguely remember reading something about the firing sequence that maybe while waiting for the other piston to fire and giving it too much gas it couldn't handle the rev and stalled.
 
Anyone know what I'm talking about? LOL! I could very well be crazy.

[pattonme]

My money is on the fuel mapping set to so gosh darn lean, that when you crack the throttle plates the sudden in-rush of air is not responded to by the ECU and you kill the motor. Adjusting the TPS moves the signal voltage sufficiently that the ECU notices faster and gives it a little more fuel and you stave off the stop. Aftermarket exhaust with no jetting changes (aka EJK) just makes this propensity more likely.
 
That people keep doing this on sequential downshifts and other posts about popping on decel and such says to me that the ECU is programmed badly. If the servo is letting in extra air as it's programmed to do, then it sounds like they are nearly turning the fuel off instead of feeding in enough to maintain a burnable mixture. This is not a new problem with Yamaha (or any of the Big4 frankly). You'd think they would have it figured out by now how to "trickle" fuel in. It's not like they haven't got it "sorted" on the R1 and other more recent efforts? Do none of these teams bother to compare notes? It doesn't actually die on your while you're doing the decel because the tire is dragging the engine around even though it should have stopped for lack of fuel.
 
I haven't done a TB sync on a FZ but I'm going to guess the problem has less to do with equalization between the 2 injectors (and throttle plates) as it has to do with getting the sensor attached to the throttle wheel to generate the right voltage for the ECU to monitor. Typically it's anchored by 2 screws in a slotted cover on the side and with a volt meter you measure the output (or is it impedance? I only ride carb bikes because I despise FI for just this sort of nonsense) by twisting it slightly one way or the other. The manual will specify what the measurement range and target is. I might try setting it on the high end of allowable values and see how that fairs.

[Guest Ralph]

No they fire unevenly, more like a V twin,
number 1 fires then when the crank as done 270% number 2 fires,
then after 450% number 1 fires again, it's one reason why the
motor does not seem to rev as hard as most twins.
 
The TB sync seems to help mine as not cut since but I am sure
your right about it running to lean it is so lean at tick over
that when you touch the throttle it just gets over whelmed by air
before the injection can react, a slowish tick over doesn't help.

[rick]

Just had a look in the service manual. The TPS can be adjusted, but only in conjunction with the diagnostic tool hooked up. There's a range of values that it can be set to, but they appear to be w/o units. If there's 5 volts going in, when the throttles are closed, it might be 5V going out. Then again, it might be not.
 
The TPS on my Aprilia is not mechanically adjustable at all. It has to be zeroed with Tune ECU or the dealer's tool (dealer/tool - how redundant) plugged in. And even then, when the throttle is closed, it does not read 0%
 
There's also a "learned" function that the IAC is part of according to the manual. Will have to do more reading as to what this does.
 
In the meantime, I'd not mess with that TPS unless you can hook it up properly.
 
Yeah, it's probably set up right on the ragged edge of too lean. With that 270 degree crank, there's a big chunk of 1 rotation where the motor is floating. The transition between fully closed throttle where the air is only getting in from the IAC and then having the throttle plates cracked just a hair is probably making it too lean -blahh, it dies.
 
If the TBs are not perfectly synced, this can make it all worse. Mine did't start to stall until I had about 500 miles on it. If it's learned something, it needs to be re-taught. Really need to get my gauges on it.
 
I love the sound and feel that this odd-degree crank makes. It's as close to a Ducati as I need to get. Even makes my Rotax's 60 degree V twin sound sewing machine like
 
Ralph, I take it yours hasn't stalled since you fine tuned the sync?

[Guest Ralph]

Not yet a good few hundred miles but I sometimes get the feeling it is going to,
when all's well you can with the engine hot just very gently open the throttle
and the revs will just creep very slowly and smoothly up, if it's thinking of
having a stall it has a slight stumble as though it's missed a beat which I think
it as then picks up, it used to do it when ever it got hot but since the tb sync
only now and then and it as not cut, try it when hot it will do it on the stand
in neutral, just barely touch the revs, pulling the clutch helps stop it likely
as that is supposed to retard the timing a little and that's likely why they seem
more prone when the clutch switch is disconnected. What wouldn't I give for a good
old tick over adjustment screw.

[pattonme]

damn computers will be the death of us. And engineers trying to be too cute by half.

[rick]

Perhaps, but FI is wonderful when it's right. My Futura has never in 12 years been on the diagnostic computer. It get's near 50 mpg w/o getting out of 5th gear ( it's geared to a legit 150 mph in 6th) and it's been very reliable and an easy starter - even after a 4 month layover. .
 
I've got a buddy's 1989 750 Gixxer in the garage with gummed up carb jets. Once those are cleaned up, we'll need to figure out why it just dies now and then w/o warning. Won't be any easier to fix w/o a computer hook-up. I'm way too old to contort my body into that bike's committed riding position, lol. It's just brutal.
 
 
 
 

[Beemer]

Mine stalled about half a dozen times while idling at traffic lights during the break-in but hasn't happened in 500 miles since the 600 ml. mark. I'm sure the first oil change gets rid of a lot of metal particles, that engine was tighter than .......... never mind.

[rmdet]

Happened again tonight... 
Rolled off throttle, clutch in, downshifted from third to second... Engine died.
 
...

I had not been watching this thread, as I figured you all may just be the unlucky few with this glitch... I had only 3 stalls in the first 100 miles and it disappeared.  
Now, at over 600 miles, I just had 3 stalls in 2 days. Two of them were when downshifting into 2nd and going at a normal mid-speed for 2nd gear. The one that really made me unhappy was coming off the expressway exit ramp merging onto a very busy 4 lane road at an intersection.  Luckily, I was quick to clutch/restart while still rolling, so all was well, but it was unsettling nonetheless.
 
 
 

[jerryv]

This seems different.  My stalls have always been from stop to start (going into 1st gear).  
 

Happened again tonight... 
Rolled off throttle, clutch in, downshifted from third to second... Engine died.
 
...

I had not been watching this thread, as I figured you all may just be the unlucky few with this glitch... I had only 3 stalls in the first 100 miles and it disappeared.  
Now, at over 600 miles, I just had 3 stalls in 2 days. Two of them were when downshifting into 2nd and going at a normal mid-speed for 2nd gear. The one that really made me unhappy was coming off the expressway exit ramp merging onto a very busy 4 lane road at an intersection.  Luckily, I was quick to clutch/restart while still rolling, so all was well, but it was unsettling nonetheless.
 
 

 

[rick]

Took a 40 mile ride today. 1st decent ride of the season for me. The roads in places still look strafed by rocket fire - sheesh.
 
Managed to not stall once. Got real close early on, but then it settled down and gave no hint of stalling - just as it should be.
 
When I got home, I got my gauges on the ports while it was still good and hot. The sync was as good as my gauges are gonna say. So back went the hose and plug w/o touching that air screw.
 
Figures, eh?

[Guest Ralph]

Rick or anyone else that is interested.
when your bike is good n hot if you just touch the throttle in neutral with clutch out a few times
does it sometimes seem to just miss a beat or stumble? if so try it with the clutch pulled in is it
the same? on mine it hardly ever does it with the clutch pulled in, I think this is due to the timing
being retarded when the clutch is in, and that's why they seem to stall more with the clutch switch
disconnected, now if you pull the clutch slowly listen for the click as the switch operates, it on mine
is a long way, I reckon that if I shortened the operating rod on the switch so it clicked sooner there
would be less chance of it stalling, not that it as stalled since the balance but what do you think.

[rick]

Interesting. Why is the timing retarded with the clutch pulled?
 
I'll have to pay attention. I actually took a bit of slack out of my cable as i like having the clutch catch pretty far out. I guess that means my switch has already out of the picture.

[Guest Ralph]

Don't really know why they do it but likely to tame the engine down when it as no load and help with slow running,but do it they do,
the tighter/ less play you have the worse it is as far as the switch goes, on cars they are often called
anti stall switches but I have never looked into how they work just replaced one or two when the car
comes in with stalling issues when slowing down. ideally you want the switch to click before the clutch
looses all grip as then the gearbox is turning the engine so it cant stop the engine is then in better
shape to keep it's self going when it looses all drive from the gearbox.

[rick]

Oh, I was thinking the other way round obviously. Mine has never stalled while downshifting - only when pulling away from a stop.
 
Mine ran so well this past weekend out in the country with little to no stop-go and it ran better and better the longer I had the revs up. Have to wonder if while running in closed loop (lower RPMs and lots of idling), it's running very lean and that has some learned LTFT causing issues.
 
Yamaha will get to this w/o really admitting there's a problem - just like the remapping that was done to the new FJ and Z9s. Come 2016, there will be a new map we can all pay 1 hour labor, that fixes this.

[Guest Ralph]

Took all but the slightest of free play out of the clutch today and the thing stalled at the very next junction
and it's not done it for about 750 miles, interesting.
 

[rick]

Interesting indeed!
 
I can go back to where the cable was adjusted from the factory, easy enough. There's a detent built into the adjuster. Weather's looking a bit dodgy this weekend, but hoping to get out. Will give that a try.

[so1102]

Took all but the slightest of free play out of the clutch today and the thing stalled at the very next junction and it's not done it for about 750 miles, interesting.

forget where I saw it, but they recommended you have about 4mm of free play at the lever, which is approximately the thickness of the thinnest plastic part of your key 
 

[rick]

Gonna do that measurement on mine is as soon as I get home. I'll gladly trade get used to the clutch catching in a closer spot if that'll make the stalling quit forever

[Guest Ralph]

Yep I was doing it as a test trying to figger out why some stall and others don't.

[rick]

OK, I'll add more confusion to the mix.
 
For starters, by my calipers, the width of the key is 4.5mm at that narrowest spot in the middle.
 
The owners manual(it's right in front of me as I hunt&peck calls for 5-10mm of lever play measured out at the middle of the ball - at the end of the lever. This translates to a 2mm gap up at the pivot! That's less play than I had it and a full turn less on the adjuster than it came from the dealer. -
 
If you make that gap 4mm, the freeplay measured out at the end is closer to 15mm. Using the ignition key as a gauge will make it well out of "spec" and might even result in some clutch drag.
 
As for the switch, any one of those adjustments will have that switch clicking before the clutch is let out completely. the 10mm measure it will click long before the clutch is done working.
 
My next ride, I'll try it in both positions. It will be easy as I'll just have to loosen the adjuster by 1 full turn to get back to that 4mm gap.

[pattonme]

This whole malarky strikes me as totally unnecessary. Why is there a switch in this system at all? And what issue was Yamaha ostensibly trying to solve? The 'pat' answer to clutch lever settings is 2mm gap at the pivot end of the lever since that's the one that is easy and consistently measurable. Anyone tried taking the switch out of the equation?

[Beemer]

Mine stalled about 6 times during the break-in period while sitting at a light and not one stall after that until about 500 miles later. Two days ago I was pulling out of a Burger King and just after I let out the clutch and got moving I started to turn/lean left (had both feet on pegs) and the thing stalled on me. The bike started to go down but I threw my foot out in time to stop it from falling over. I don't think the extra weight of a Double Whopper made any difference. Was embarrassing more than anything. Makes you look like a noob that doesn't know how to ride. Anywho, I'm calling my dealership about it and see what they say.