Issues restarting bike when cold - pics and video included

[alpalwal]

I recently got this '15 RC390 and it has been working great overall except for this one issue.

When the bike is cold, it starts perfectly fine. After it's running, if I start riding before it's fully warm, it has a tendency to stall and not want to restart.

After searching around on the forum, I have a feeling that it's related to the evap canister or something with the vacuum lines.

I pulled the left fairing and here's what I see:

This line is normally pointing down towards the ground. It's short because it was sitting against the exhaust and it got a hole burned in it. I just shortened it and put the cap back in the end.
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This line is more curious. It's a Y tee and one end goes to the coolant reservoir, one goes down to the ground, and one goes under the tank. Is it supposed to be this way?
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Here's a vid of the issue. I start the bike up and it runs fine, after I intentionally stall it and try to restart, it doesn't want to start.

Eventually it'll fire up but it takes a while. I tried opening up the tank as well in case it was vapor locked but that didn't seem to help.

https://youtu.be/VF0nsYP4zZY

Any ideas what's going on here?

 

[cornerslider]

I have experienced the EXACT same thing you did in the youtube video..... It can be a little unnerving, and doesn't inspire much confidence in the bike. Here is my story: I always try to use NON-OXYGENATED, 93 octane, premium fuel. I was out on a ride one day, and I was running out of fuel, and options..... I bought a full tank of regular unleaded- 87 octane from a generic/no name station- (they didn't have anything else). The bike ran great like it always has. The following day, it did just as your bike did. I'm not a fuel guru, and I don't claim to be one, nor can I explain why this happens??? But- my bike did EXACTLY the same thing your bike (randomly of course), and then would run perfect after it warmed up. Luckily, the RC has a small tank , so I burned the fuel out of the tank until the "low fuel" displayed on the dash.... Then I headed towards my favorite station that sells my preferred fuel. I topped it off with the "good stuff", and I haven't had a problem since!!! That was 1200 miles ago .... I always run the "good stuff" now. I would almost rather run out of fuel on the side of the road, than use "bargain fuel"...... Try running the fuel out of your tank (or drain it), and fill it up with some premium, non-oxygenated fuel, and see if it self corrects. Please keep us posted on your results. In response to your pictures, everything appears normal. I'd say 99% of the RC owners out there have a melted over-flow hose. KTM kind of dropped the ball on that one..... The "Y fitting/routing looks normal too. No kinks, cuts, etc.

 

[alpalwal]

Did the bike do it when it was warm too? It seems for me that it only happens when it's cold right after startup.

Out in CA, the best we have from the pump is 91 so hopefully I don't need to start scrounging around for 93 non-oxengated just to get it to run right!

 

[alpalwal]

It looks like I have the same issue as this thread but it didn't seem to get resolved there either:
http://www.rc390-forum.com/forum/en...7-cutting-minute.html?highlight=evap+canister

 

[cornerslider]

Did the bike do it when it was warm too? It seems for me that it only happens when it's cold right after startup.

Out in CA, the best we have from the pump is 91 so hopefully I don't need to start scrounging around for 93 non-oxengated just to get it to run right!

My bike only did it when it was cold/not warmed up. I'd estimate it happened maybe 4-5 times on that tank of gas. I'm pretty sure the bike is designed to run on 91 octane. I'd have to check the owners manual for sure? I just use 93 octane because that's what my local station carries in a non-oxygenated fuel. I'm fortunate to have a local station about 5 miles away that sells a variety of fuels, all the way up to 110 octane race gas. What I do now (at a minimum) , is nothing less than 91 octane from a reputable station. I obviously prefer non-oxygenated, but it's not a deal breaker..... I haven't had a single issue since I had that one "bad tank" -

 

[KTMGene390]

First, I'd like to say: I respect everyone's opinion in this thread and mean no disrespect but...

The bike is designed to run on pump fuel whether that's 91 in CA, or higher octane in other states. Unless your fuel has water in it, is extremely old...it is not the reason why the bike stalls when cold. If that were the case every bike would be doing this, but rather other factors such as Idle being too low, throttle body being dirty, if you removed the emissions canister (CA only models I think), and did not plug the throttle body with a cap after removing the hoses. Other factors like very high altitudes, spark plug boot cap (which is notorious for coming loose easily) or other factors like a dirty fuel injector are to blame...

Running race gas in a stock motor is a complete waste of time and money. If you really want to do that VP MR12 will give you a small boost but even that's a waste and it will burn out, over time your O2 sensor because it is leaded. Even that is likely to be a waste without a tune. Who wants to on a stock motor anyways.

This may read as a rant but it's more of an FYI. Hopefully, everyone having trouble figures out the cause and can enjoy their bikes.

Wanted to add: my bike stock would have a hard time starting in gear when cold or warm if I accidentally stalled it out but would start just fine in neutral. Also, if you overfill your tank often and you have an emission canister it can become saturated causing starting problems.

 

[alpalwal]

First, I'd like to say: I respect everyone's opinion in this thread and mean no disrespect but...
Wanted to add: my bike stock would have a hard time starting in gear when cold or warm if I accidentally stalled it out but would start just fine in neutral. Also, if you overfill your tank often and you have an emission canister it can become saturated causing starting problems.

Interesting. I'll try putting it in neutral next time to see if that helps.

How would I overfill my tank? Is there a certain line I'm not supposed to cross?

I do have an emission canister and so maybe that's the issue. Is that something I can just blow/shake out?

 

[KTMGene390]

Interesting. I'll try putting it in neutral next time to see if that helps.

How would I overfill my tank? Is there a certain line I'm not supposed to cross?

I do have an emission canister and so maybe that's the issue. Is that something I can just blow/shake out?

Add fuel to just below the filler neck in the tank. The extra fuel in the emissions canister if any should evaporate over time.

 

[cornerslider]

First, I'd like to say: I respect everyone's opinion in this thread and mean no disrespect but...

The bike is designed to run on pump fuel whether that's 91 in CA, or higher octane in other states. Unless your fuel has water in it, is extremely old...it is not the reason why the bike stalls when cold. If that were the case every bike would be doing this, but rather other factors such as Idle being too low, throttle body being dirty, if you removed the emissions canister (CA only models I think), and did not plug the throttle body with a cap after removing the hoses. Other factors like very high altitudes, spark plug boot cap (which is notorious for coming loose easily) or other factors like a dirty fuel injector are to blame...

Running race gas in a stock motor is a complete waste of time and money. If you really want to do that VP MR12 will give you a small boost but even that's a waste and it will burn out, over time your O2 sensor because it is leaded. Even that is likely to be a waste without a tune. Who wants to on a stock motor anyways.

This may read as a rant but it's more of an FYI. Hopefully, everyone having trouble figures out the cause and can enjoy their bikes.

Wanted to add: my bike stock would have a hard time starting in gear when cold or warm if I accidentally stalled it out but would start just fine in neutral. Also, if you overfill your tank often and you have an emission canister it can become saturated causing starting problems.

No disrespect received . Knowledge is why we are here (at least why I'm here). If any one of us can help another member out, I think that's awesome . Alpalwal, please keep us posted on what you figure out with your bike-

 

[alpalwal]

I tried restarting in 1st and neutral and neither one helps.

I only have about 2 bars of gas left and it has sat for a couple days so that shouldn't be an issue with the evap canister.

I got a new battery since my old one wasn't feeling super strong but that didn't help either.

Any other ideas? I was thinking of removing the evap canister to simplify things a bit but I haven't found any good instructions on it besides the couple pictures here:
http://www.rc390-forum.com/forum/electronics/797-evap-emissions-solenoid-purge-valve-removal.html
http://www.rc390-forum.com/forum/ktm-rc-390-general-discussion-forum/734-big_surs-race-build-2.html

 

[shreeshar7]

My bike had a very similar issue after engine rebuild.
Would start and idle fine when cold but when I engage gear and try to move the bike with slightest thtottle and during gear shifts ( on off throttle transitions) the bike would stall.
The issue would go away once the bike heats up a little.
.

Later my throttle body was cleaned and the shims were readjusted..
Now runs fine.

First check intake, fueling and ignition.
Then get valve clearences n shims adjusted.