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Ok, I take back what I posted a few months ago the problem is actually the ignition itself dealer will replace it along with the fuel tank lock and the one for storage.


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That's just really weird. Good luck and post back what you find out!
I dropped by and described the issue to a tech. He seemed confident he could resolve the issue. Brought the bike in yesterday, and he starts heehawing that I'm blipping the throttle 3-500 rpms, and I'm trying to explain to him that it's just one of the manifestations of whatever the root cause is. Anyway, he said he'd have a look and contact Yamaha, but if they couldn't resolve it, then I'm on the hook for $90 diagnostic fee.

Oh yeah, we discovered a small amount of coolant has blown out the top of the radiator cap.

If they can't fix it, here's my planned diy list: plugs, wires, injectors, thermostat, water temp sensor, tps, maf, idle air adjustment, throttle body sync. I don't really want to invest more $$$/time into pcv + dyno shop tuning just to get the bike to not die at a stop light.

I wish I knew if this problem started before or after the recall work was done.
 

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The tech "adjusted the throttle cable" to "remove intake air bubbles" ... he off-the-record hinted at getting a full system + pcv + tune, to actually fix the issue ("too lean and idle too low"). Or perhaps the start-up auto-choke feature is malfunctioning. He said the throttle body sync was good.
 

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Okay, everything in the service manual related to fuel/air seems like a dead end without the Yamaha diagnostic tool. So, I took the air filter out, let it idle until the cooling fan cycled a couple times, jiggled the throttle while listening right there by the air intake. Every time it dies, there's a distinct loud PSHHT sound from the intake. That's an intake backfire, isn't it?

My google-fu found another off-idle stumble/die thread for a different Yamaha motorcycle, and the solution sounds like the two prohibited air bypass screws: "Airscrew adjustment to fix the off-idle stumble that some have complained about, especially in the California model."

So, I adjusted the throttle stop to keep the throttle open slightly more, then adjusted the 2 air bypass screws about 1/4 turn clockwise each. This seems to have greatly reduced the off-idle cough, but it still died once. =/ Will try the procedure once more, as I only adjusted by 1/3 of the poster's recommendation.

edit: I think it's actually two problems. The off-idle cough seems cured. But the instant 0 rpm / loud intake event remains. Maybe switching to premium gas would help fight the hot'n'lean condition. [Premium didn't help anything.]
 

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It actually sounds like you have a vacuum leak and a throttle body sync problem. There is a thread somewhere on the R6 forums about how to sync the throttle bodies yourself. If you can fix that, you might fix your stall issue but to me the PSHHT sound could be a vacuum line issue.
Well, the stall is somewhat intermittent. I will try some carb cleaner to look for a leak, but not expecting anything from that. The problem is clearly worse the warmer the bike gets, and when the cooling fan kicks on and starts pumping hot air around my legs and bike's intake, then it is at its worst. That's why I think it's afr. Maybe unique to California model ecu.

I did a tb sync on my Ninja 250 before, so I'll try to do that next weekend + inspect/replace spark plugs. Do you know if the R3 has a thermowax setup for cold starts, or is it all electronic via isc? If thermowax unit fails, then the throttle body will be stuck in cold mode all the time. Tech claimed it could be that, I forgot about that one. I don't think that's it, b/c if I start the bike and immediately ride off, it also coughs while cold, bucking me hard.
 

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To be honest, I don't know much about the bike at all - I'm just drawing theory from basic engine knowledge. If we think about it logically - engine stalling while warm, and if you bump the idle, it doesn't do it. So that leads to the conclusion that there is something about the fuelling.

Maybe your ECU needs to be reflashed? What if its as simple as the ECU not handling the idle correctly? Grasping at straws here.
 

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To be honest, I don't know much about the bike at all - I'm just drawing theory from basic engine knowledge. If we think about it logically - engine stalling while warm, and if you bump the idle, it doesn't do it. So that leads to the conclusion that there is something about the fuelling.

Maybe your ECU needs to be reflashed? What if its as simple as the ECU not handling the idle correctly? Grasping at straws here.
Today I entirely closed the idle air bypass screws (for the record, that was approx 1.35 turns clockwise), and set the idle to 1500 with just the throttle stop adjustment. Rode the bike 2 hours without any issues, and tried like crazy to get it to stumble at every stop light. Now, it's not 100F in summer yet, but this is clearly a tremendous improvement. I need to check cold start tomorrow (though "cold" is relative at 50F overnight lol).

If I want to play with a PCV, then I have to get someone outside of CA to buy and send to me indirectly, they are illegal here technically.
 

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So what's the idle air bypass for anyways? I'm guessing it's an emissions thing? It sounds like you've licked the problem with a workaround but clearly that isn't the way the bike is supposed to be setup. Will be interesting to see what happens though.
"There is essentially no difference in efficiency between the technique of bypassing the throttle butterfly and operating the butterfly itself. "
"The most common failure mode ... an engine that fails to maintain idle RPM and frequently stalls."

https://en.wikipedia.org/wiki/Idle_air_control_actuator

Shooting from the hip here, it allows for finer control of idle rpm and control by ecu, so by shifting idle to the main butterfly, the bike's idle may vary more, but by manually eliminating the bypass, it removes an apparently troubled crossover point.

What is curious is that the other Yamaha thread's solution was that the bypass needed to be opened up ("bypass almost closed for emissions reasons"), but that way immediately made the situation worse here. Replacing the throttle body would probably cure the bike, possibly some corner case set of minor production variations that didn't pan out well.

Okay, it started fine this morning, and still not stumbling. Fingers crossed!!!
 

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Mine cut out twice as if you hit the kill switch. Once from a stoplight while in first gear. The second time was after about 40 minutes of riding and doing about 50kmph it just cutout. Good thing I was able to pull over before getting rear-ended.
 

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I have a 2019 R3 with 3000 miles on it. I have kept up with the maintenance on it as far as oil changes, chain adjustments, etc. I was pulling into a parking lot in 2nd gear and my bike started to jump so I down shifted into first gear thinking I was going to slow in second causing it to jump but when I went into first gear, I had to clutch pulled in, and my bike shut off and my oil light came on. I parked and checked the oil level and to see if there were any oil leaks (Which was fine) and tried to start it again and it started right back up with no hesitation. any suggestions on what happened or what I should check?
 

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I was pulling into a parking lot in 2nd gear and my bike started to jump so I down shifted into first gear thinking I was going to slow in second causing it to jump but when I went into first gear, I had to clutch pulled in, and my bike shut off and my oil light came on. I parked and checked the oil level and to see if there were any oil leaks (Which was fine) and tried to start it again and it started right back up with no hesitation. any suggestions on what happened or what I should check?
It's proper for the oil light to be on when the engine isn't running (because no oil pressure). Sounds like a possible fueling hiccup. I'd just keep riding, unless it starts happening with regularity. Maybe possible sign of an ailing fuel pump? Only time will tell.
 

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I was at a stop light just chilling waiting for the light to turn green when all of a sudden the engine just died. As if I hit the cut off switch or something. I started it back up and off I went. I believe I read somewhere here that someone's engine cut out once when they were in motion. I tried searching but couldn't find that post.

Now that I think of it, the engine also refused to restart for me once after I shut it down to park it, then tried to restart it after a minute or so. Took me 4-5 tries before it fired back up. This hasn't happened again, but sometimes I feel like the engine does only barely start. As if the starter is geared too short or something.

Anybody else ever experience this kind of stuff? I have to be honest. My Honda never let me down even once. I've had the R3 for less than 2 weeks already have had two issues.
How many miles are on the bike?
 
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