2018 RC390 Stalling (Yes, I know it's a common issue and I've searched)

2018 RC390 is having some stalling issues in two circumstances. I understand this to be a common problem, but there are no resolutions (apart from one I've listed below) OR people just forget to reply with their resolution.

Brand new bike, less than 100 miles.

Two separate issues:

1. Within the first 10 miles, when downshifting into first gear the engine stalled. It did this several times as I rode the bike home, including on the freeway when I downshifted to lane split. Each time it started back up.
-- I cleaned the side stand sensor and magnet and added a washer in as spacer.

2. When idling and with slight revving, the engine stalled. Didn't matter if it was cold or warm.
-- Unclear on this.

Yes, I'm aware I can take it to a dealer. I still would like to get an idea about what's happening.
I've experienced issues where the engine would die during the first few hundred miles on other new bikes I've owned and over time it stopped. I attributed this to the ECU, but it only happened once or twice (not nearly as consistent as what I'm experiencing now).

Thoughts.. ?
 

ReidMcT

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Mine did this. I let it just sit and idle for about 15 minutes, and it hasn't happened since.
 

ReidMcT

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Maybe it lets the ECU figure out optimal configurations.
 

mdabyo

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mine was the spark plug cable. it was so loose on the plug that it would vibrate and lose connection and die.
 
My '17 was having this problem for a bit. I took it to the dealer because at the time my dash was showing "abs failure" and it stalled twice on the way to the dealer.

I mentioned it to them as a side note and they said it was likely related to my abs failure.

As it turns out, the rear abs wire just came unplugged (connector was ziptied to the frame somewhere above the exhaust on the right side if you wanna go looking for it).

They plugged that back in, no more abs failure, and I haven't had it stall on me ever since other than from my own noob skills

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John390

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as for the stalling issue, I had this and it was annoying as hell, and downright unsafe in certain situations.

at first I tried a Rapidbike Evo because I know the bikes are very lean from the factory, and this helped a lot, but still did not fix it fully.

What finally fixed it was proper clutch adjustment.

If the clutch isn't realeasing fully, it will drag and stall the engine.

I adjusted the engine end of the lever so that it still has enough free play, but not more than that.

I adjusted the top one the same way.

Then (and this is important) I adjusted the adjustable lever to give the most travel. You can watch the lever on the clutch cover move, and if you adjust it to anything but the most travel, the lever doesn't move as far.

I also have my aftermarket adjustable lever setup this way as well.

No stalling at all now, not ever, not in may hundreds of KM. If I turn it one or two notches down, I will get an occasional stall.
 
Thanks. I tried letting it idle and then I checked over the clutch cable.

I think I have a different problem than what's been mentioned. It has only happened in first gear at low revs or coming to stop, but only when going through the gears quickly then stopping. For instance, if I slowly downshift or don't downshift at all coming to a stop, it hasn't happened. Don't know if this has anything to do with it or not.
 

John390

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thats exactly how mine was too. only stalled when putting it in 1st gear.

Just do yourself a favour. Adjust the lower clutch cable to have just enough play to ensure that it fully releases.

Then do the same with your hand lever.

Then adjust your hand lever adjuster to full movement.

Try it. If I put my adjuster (not the one at the cable, but the manual, no tools numbered adjuster) 2 notches closer, it WILL stall occasionally in 1st.
 

Tom

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It's also worth a try to see if the evap system may be causing this. Our charcoal canister is really small, so if it gets flooded or starts having issues, you will be pulling in a lot of extra fuel. The downshifting part you mention is what lead me to this as being a possible candidate.

You can try plugging the hose that leads back into the motor from the evap valve, and see if it helps at all. You'll probably get a check engine light while it's plugged, but I wouldn't worry about it while you are testing.
 

John390

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thats a good thought Tom.

I'd expect that to only be a couple of stalls or a few in a short time. As the bike re breathes the vapours and the excess vapours evaporate, the canister will get back to normal fairly quickly. anything happening over higher mileage and time intervals, I suspect is not this, or at least not JUST this
 
Adjusted the clutch. Bad weather until the weekend, so I won't be riding until then.

Regarding the evap canister; is it worth removing? I've removed it on all my other bikes and have not had problems.
 

Tom

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I'll be removing mine just because it's getting in the way of my wiring harness to the splice connector for the O2 sensors on my wide band commander. I think the trickiest part is to find a way to route the gas tank's vent tubes so it's not in the path of the rear wheel. The last thing I want is for a drop of fuel to land in my contact patch mid corner.
 
From what I've experienced if you are downshifting and cracking the throttle on above 10250 the ECU sends enough fuel through the injector that it essentially floods/stalls the engine. This is only an issue for models up to 2016 so if it is newer then that its most likely another issue.
 
OK, update. Did a fair amount of canyon riding over the weekend -- no issues with stalling. I tried it out in traffic a bit, too (because that's where I was noticing the issue) and so far so good. I want to do more riding before I confirm that it's fixed.

Here's what I did..

John390's recommendation on adjusting the clutch -- I left very little play on the clutch actuator and moved the adjuster on the lever to the furthest away from the handlebar.
Washer to space out the magnet sensor on the side stand
Let the bike idle for 15 minutes
 
Just following up here.

All of the above changes were made, but I noticed that it would still stall - occasionally - at low revs and in first gear primarily. There has been a lot of discussion about how lean these bikes run from the factory and this being a contributing factor.

Well, after my first valve adjustment, all of my valves were out of spec. I haven't had issues with stalling since all valves have been adjusted... I'm pretty convinced that this was the issue.
 
Well, after my first valve adjustment, all of my valves were out of spec. I haven't had issues with stalling since all valves have been adjusted... I'm pretty convinced that this was the issue.


Quick question about your valve adjustment. Did you have to drop the engine from the frame or was it easy enough to do with the engine still on the frame? I'm probably going to have to check my valve clearances in the next couple thousand miles

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ReidMcT

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Quick question about your valve adjustment. Did you have to drop the engine from the frame or was it easy enough to do with the engine still in the frame?

Having done it both ways I will say that it is easier to do on the bench, but definitely not worth the trouble of removing and reinstalling the engine.

Assuming you cut out the rubber sound deadening mat and do not wish to retain it. It is totally in the way and extremely difficult to refit with the engine in place. Heck, even shredding it with a knife and pulling it out bit by bit is a chore.
 
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MuTToN_DaGGeR

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So has there been no definitive answer to this issue?

I am dealing with a similar stalling issue:

If I slow down to come to a stop, doesn't matter if im in any gear or in neutral, as soon as I stop it will cut out, sometimes before im stationary (at a VERY low speed).
Sometimes while coming to a stop (in gear or neutral) the idle would be ever so slightly high, then as I slow down to basically the stationary point, it will go to its normal idle speed.

Is there something in the ECU which keeps the idle a little higher whilst on the move?
To test this, I got up to a speed and held in the clutch, the idle was higher than normal and as I stopped it went back to its normal idle speed.

The issue I have isnt with the strange idle, its with the stalling so back to that.

My theory is that the ECU would have a a fuel map for on the move and a fuel map for while you are stationary, maybe there is conflict between the two when transitioning between moving and becoming stationary.

Im on a 2015 model with 35K on the clock, I rebuilt the motor after the head-gasket went, the shimming was done, head skimmed the whole 9 yards.

I should add that I took the bike to KTM and they scanned for codes, they told me that it was a faulty Lambda sensor. R2000.00 later I installed the new part and it changed nothing.
Im going to have to go back and re-scan the bike and find out what im going to spend my money on next.
 
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