Hi All,
Just received my 2017 EX yesterday. Will post some pics soon.
I noticed there's a periodic hum sound coming from the gas tank after shutting off the bike. Is this normal? I searched the forum and didn't see anything about it. It's sounds like a little pump or electric motor. I'm guessing it's the EVAP system, but I think it's been humming periodically all night since yesterday so why would it still be happening?
Thanks, any help is appreciated.
That's a new one. Are you certain there isn't an insect caught up in there somewhere?
One way to eliminate that possibility is removing the negative battery cable while the sound is present. If the noise continues, it has to be a critter.
Let us know what you find!
(06-24-2021, 04:50 AM)le_penseur_imp Wrote: [ -> ]Hi All,
Just received my 2017 EX yesterday. Will post some pics soon.
I noticed there's a periodic hum sound coming from the gas tank after shutting off the bike. Is this normal? I searched the forum and didn't see anything about it. It's sounds like a little pump or electric motor. I'm guessing it's the EVAP system, but I think it's been humming periodically all night since yesterday so why would it still be happening?
Thanks, any help is appreciated.
Indeed haha! It is definitely not an insect, but I just went back to bike and it's not doing it now. I was looking at the service manual and it looks like the EVAP system has a solenoid. My guess is it's opening and closing the valves. The bike hadn't been started in awhile and just got to me in CA from FL so the gas may be going bad as well.
I will run a new tank through it and report back.
(06-24-2021, 04:59 AM)LakeWylieJoe_imp Wrote: [ -> ]That's a new one. Are you certain there isn't an insect caught up in there somewhere?
One way to eliminate that possibility is removing the negative battery cable while the sound is present. If the noise continues, it has to be a critter.
Let us know what you find!
(06-24-2021, 04:50 AM)le_penseur_imp Wrote: [ -> ]Hi All,
Just received my 2017 EX yesterday. Will post some pics soon.
I noticed there's a periodic hum sound coming from the gas tank after shutting off the bike. Is this normal? I searched the forum and didn't see anything about it. It's sounds like a little pump or electric motor. I'm guessing it's the EVAP system, but I think it's been humming periodically all night since yesterday so why would it still be happening?
Thanks, any help is appreciated.
There's nothing electrical that would or should be making the noise. I would take the seat off, pull the rear tank mounting bolt out, and check for a kink in the small hose that vents the gas tank.
Pressure built up inside the tank from heating and cooling should be going out through the hose to the evaporative emissions canister. The canister is charcoal filled, traps the vapors.
If somehow, the tank was overfilled well above the bar, fuel may saturate the canister to the point of clogging it. Open the gas cap to see if you hear a pressure release or a vacuum sound.
The other possibility is that the fuel pressure in the lines could be bleeding out through a sticking injector, or through the fuel pump's bypass valve. If you happen to be around when it's making the noise, open the gas cap to see if it gets louder. The evap solenoid only activates when the engine is running.
The line should hold 50psi for at least a couple hours, or maybe all night. When you cycle the key on, note how long it takes to build pressure back up compared to when you have just shut the key off, then back on.
I will buy the charcoal canister evap system suggestion.
My ol' Aprilia did it all the time, even 30 to 60 minutes after a ride. It would sound like a loan calf moaning in the distance.
There were no electrical interventions. The process was passive.
This is particularly most often in warmer weather riding seasons.
(06-24-2021, 04:50 AM)le_penseur_imp Wrote: [ -> ]Hi All,
Just received my 2017 EX yesterday. Will post some pics soon.
I noticed there's a periodic hum sound coming from the gas tank after shutting off the bike. Is this normal? I searched the forum and didn't see anything about it. It's sounds like a little pump or electric motor. I'm guessing it's the EVAP system, but I think it's been humming periodically all night since yesterday so why would it still be happening?
Thanks, any help is appreciated.
It’s happy?
Update, the sound immediately stops when I open the tank cap, but there is no pressure release occurring.
Hi there, the CB makes a lot of strange noise when it’s off and cooling down (in the garage post ride out). Often hours later I could be in the garage completely quiet when the bike would just start making funny noises for a few seconds or more then fall silent again. Almost like a haunting gurgling noise that is very difficult to describe. I wouldn’t say it was humming but I think this might be what you mean and is nothing to worry about. It’s the modern gummings evap system doing its thing. That’s all.
(06-25-2021, 03:22 PM)le_penseur_imp Wrote: [ -> ]Update, the sound immediately stops when I open the tank cap, but there is no pressure release occurring.
Mine does the same, I've stopped trying to find out why now because it does not seem to be doing any harm or affect the bike in any way.
Glad mine is not the only one! I think they're just hibernating, getting ready for the next ride lol.