Warm weather starting issue

[Zachariah311]

Just bought a black 2015 Concours 14 a month ago with 8,000 miles on it and I'm absolutely in love with the bike. It's an amazing ride. I'm a mechanic by trade (not a bike mechanic specifically but worked on my own quite a bit) and I've done the very basic maintenance so far except the air filter but I've ordered a new one.

So the issue I had today after leaving work at 3:30pm in Cleveland with a temp around 80 F (bike sitting in full sun all day unfortunately) was that I went to start the bike while putting on my gear and it cranked over, sounded like it caught, then died. It did this two more times before starting with a little bouncy idle then was fine. I was wanting to get the opinion from people that are much more familiar with this bike/engine on what to look at first. I was planning to check battery/connections and test whether or not the tank isn't venting properly while sitting in the sun tomorrow, weather permitting, by opening the cap to see if it's got higher pressure in it. If it does, then I'd go towards the canister (assuming it has one since it's newer). I do know that the previous owner dropped it on it's right side based on the light-ish scratching on the lower fairing so maybe it's partially plugged? The bike doesn't ever stall or stumble no matter how long I run it but I don't know if this bike would act like that with a partially plugged canister though. I'm also thinking that it could just be gunk that's built up from ethanol gas that's worked loose from the cleaner I put in the tank or winter gas that's still hanging around in the area as we're just now warming up evaporating too fast causing the issue.

I have also noticed that the warm idle is closer to 1000 rpm so I need to turn that up as recommended and could also be a contributing factor.

I'm a bit paranoid about my own equipment/toys (especially my bullet on two wheels) so any and all incite is greatly appreciated. I might be overreacting since it's a new to me bike but maybe not and one of you have had a similar issue.

[Boomer]

Sounds very much like a blocked vent causing overpressure in the tank.
Normally only the CA bikes have the canister but maybe K made all their US C14s CA models after a certain date.
Definitely get the idle set to 1200 and see if it happens again.
If it does, open the gas cap, turn ignition off and on again, and hit the starter.

[lather]

Definetely keep your warm idle at 1200 or even 1300 if the throttle bodies might need syncing.

[Conrad]

Sounds very much like a blocked vent causing overpressure in the tank.
Normally only the CA bikes have the canister but maybe K made all their US C14s CA models after a certain date.
Definitely get the idle set to 1200 and see if it happens again.
If it does, open the gas cap, turn ignition off and on again, and hit the starter.

I fail to see how positive pressure in the tank would cause this. Negative pressure yes, positive pressure no. 

The OP states that the bike died right away so it couldn't be that the tank developed the negative pressure that quickly.

[Zachariah311]

I fail to see how positive pressure in the tank would cause this. Negative pressure yes, positive pressure no. 

The OP states that the bike died right away so it couldn't be that the tank developed the negative pressure that quickly.

I'm not exactly sure to be honest. I've seen it happen once and when the pressure was relieved the pump operated correctly. That was years ago when I was young and not concerned about the why it worked. I didn't investigate further but if I ever see it again I'm going to rip the pump apart to see if it's due to weak/failing bearing(s), seals, etc. As I remember, the friend of mine that owned the bike replaced the vented cap and didn't have a problem for over two weeks but replaced the pump in short order (he used my garage/tools is how I know that) because he was doing a longer trip and it was to big of a concern to him. It could've been a coincidence, I guess, but I don't know.

Weather cooperated today and the bike did it again. I shut it off, opened the gas cap with minimal pressure release, and tried to restart with the cap open. It didn't start again so I shut the tank, twisted the throttle, and it started. It idled up to around 1200ish I'd say then quickly (like a second or two) went down to 1000 rpm with a little bounce in it evening out pretty quickly. So I'm thinking the primary culprit might be the idle itself since the bike fired immediately after I gave it some throttle.

I tried looking for the idle adjustment on the left side in front of the shifter and linkage but didn't see it. The manual doesn't say anything about removing a panel or anything so I gave up since it was rather warm and it's suppose to storm here sometime soon. I'm going to look again but if someone wouldn't mind giving me a more descriptive location of it that'd be great.

Thanks for the replies.

[maxtog]

I fail to see how positive pressure in the tank would cause this. Negative pressure yes, positive pressure no. 

Agreed

The OP states that the bike died right away so it couldn't be that the tank developed the negative pressure that quickly.

If the venting system is blocked, it could develop negative pressure over time and hold it until the next starting.  However, this would normally only happen either as the fuel level dropped significantly (through riding it, which is not the case here), or a DROP in temperature (which also doesn't seem to be the case here).

Either way, the test would be to open the gas cap and try, which was suggested already.

[PeteTN_zgtr]

The idle adjuster on my 08 comes down right in front of the front-bevel drive housing. It's a silver knob on the end of a tube right in front of the silver housing. It could be tucked in behind the vent tubes. It is tricky to see.

[Boomer]

I fail to see how positive pressure in the tank would cause this. Negative pressure yes, positive pressure no. 

The OP states that the bike died right away so it couldn't be that the tank developed the negative pressure that quickly.

Most fuel pumps use a pressure sensor and if a certain pressure is exceeded, they cut off.