Rough idle and stalls, then won't start

549 Views 4 Replies 5 Participants Last post by cornerslider, 2 mo ago

Pkap

Discussion Starter · 2 mo ago

I've been trying to diagnose a mystery issue with my 2019 R3 for the past few months and was wondering if any of y'all might have some insight.

On most days, especially colder ones, the idle is rough - almost like a cylinder is misfiring or something. After a while when it warms up its fine so I'm not sure if this is just a temp thing not to worry about or if it's a secondary issue related to the main problem. Granted, Florida weather isn't too cold so I don't see why it should be this rough.

Main issue: before fully warmed up, the bike will stall with clutch fully in when given a bit of gas. Specifically, as I'm in first, clutch in slowing down to a stop or starting from a stop and give it a tiny bit of throttle it dies. When given a lot of throttle slowing down or starting, revs dip and jump back up, which is also a little weird, but the issue happens when it's just a little throttle. After stalling, it does not want to start easily. It will turn over but not start unless I apply throttle while cranking it. It started doing this recently when my engine was warmed up as well as cold.

I've replaced the spark plugs as well as the air filter. I've also been to an auto shop to test the battery and they said it was fine. Fluid levels as far as I can tell are fine too. I bought a 3 prong adapter to check OBD2 but the cable is garbage and reader won't turn on, while my local shop wants to charge 40 bucks for a scan :/

Any thoughts are appreciated about the issue or if I'm missing something when trying to check codes.

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airhead83

· #2 · 2 mo ago

It sounds like you've covered the obvious 1st steps in troubleshooting the problem. Everything on your R3 is electronically controlled. Sometimes a diagnostic from a qualified technician, like at your Yamaha Dealer, is the best route. Labor is not cheap. But throwing parts, that in all likelihood cannot be returned or refunded, at an unknown problem gets costly in a hurry. You may get lucky and stumble on the problem, but it may be a more expensive, and more frustrating, option.

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Squidward

· #3 · 2 mo ago

Sounds like a fuel delivery issue. Pay the 40 bucks and get it done right.

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xorbe

· #4 · 2 mo ago

Pkap said:
the bike will stall with clutch fully in when given a bit of gas

My brand new 2015 did this. Dealership/Yamaha blew me off, said the bike is operating normal as designed. I went nuclear with my fix, I closed the IAT and set idle with the main butterfly valve. It is quite tedious as they made it tedious, because they don't want you messing with it. It was so smooth down low after that, like a different bike. "Proper" fix is probably an ECU flash + tune, the idle is just too lean imho.

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cornerslider

· #5 · 2 mo ago

xorbe said:
My brand new 2015 did this. Dealership/Yamaha blew me off, said the bike is operating normal as designed. I went nuclear with my fix, I closed the IAT and set idle with the main butterfly valve. It is quite tedious as they made it tedious, because they don't want you messing with it. It was so smooth down low after that, like a different bike. "Proper" fix is probably an ECU flash + tune, the idle is just too lean imho.

As I was reading this whole thread, I was thinking this EXACT same thing.... I've had 2WDW flash several R3's. My wife's R3 is bone stock- and 2WDW has a flash for that too!!!! It did EVERYTHING better after the flash. Unfortunately, Yamaha chooses to meet EPA exhaust emissions by programing the throttle to operate like a light switch- It's either on, or it's off. While it makes the government happy, it detracts from the whole rider's experience. After the flash, everything fueling related got "buttery-smoooooth". The R3 is a pretty easy bike to ride, and very "forgiving" to newer rider inputs. After the flash from 2WDW, it got even easier to ride than it already was

. Even if this doesn't solve the issue you are experiencing, it's money well spent, and you will NOT be disappointed

. I recommend you start there. For what 2WDW charges for the flash, a dealer would charge you that just to "look-at-it" 😞....

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