I got a new to me 2012 Road King a week ago. I filled it up a few days ago and put the cap back on. The cap is a "Ride to LIve" type and the emblem was crooked (the writing was cockeyed) but it had been working fine. After filling the tank, I put the cap back on and clicked it til the writing on the emblem was level. This afternoon I was very low on gas so I stopped to fill up and I couldn't get the cap to unscrew no matter how hard I tried. I headed for the dealer with my fingers crossed. About halfway there and with 20 showing on the "miles to go" gauge I had to stop at a red light. I reached over and was able to unscrew the cap. I stopped at the first gas station and filled up. I put the cap back on but only tightened it down a click or two. I had 2009 and 2016 Ultras that didn't seem to mind extra clicks on the cap.

Any ideas on what is going on here? Maybe the cap was on too tight for the tank to vent? Thanks in advance.

 

My buddy rides a 2006 RK. Road Kings have that "Fake" cap you're not supposed to touch. I went to grab that one and my buddy yelled "Not that one!" The gas cap is the other one!

On my 06 Ultra there's only one cap and I can click it till the cows come home! And I leave it on the seat when I fill up!

 

Throw that POS cap away and get a real one.

 

Short answer:

I wasn't there to experience the cap being stuck. I have no 1st hand info to form an opinion whether the "stuck" condition was mechanical in nature, or pressure/vacuum related. So on a new to me bike full of unknowns, I'd start by checking that the Evap line from the tank top plate isn't plugged/restricted, and get a new cap.



Long answer:

FYI...Most of the "Ride to Live" caps are just smooth OEM caps, with a "Ride to Live" emblem stuck on the cap. Those OEM caps are supposed to click past tight without issue.


The way I understand it, and someone feel free to correct me if I'm wrong, the 2012 touring bikes have an evaporative system on the fuel tank. Earlier models just had a small nipple on the front of the tank with a vent hose.

Attached to your 2012 top plate, under your console, is a vent line that is attached to a valve in the top plate. That valve allows fumes to escape from the tank, but will stop fluids. Your center fill touring bikes and your touring bikes with right side caps, are vented caps, with a one-way valve, into the tank. The system is designed to allow air into the tank through the cap, and it vents out of the tank from the top plate valve and into the Evap line. This vent flow was necessary so the CA models could "treat" the tank fumes.

In CA models, that Evap line additionally goes through a purge solenoid, then into a carbon canister, so no "untreated" gas fumes are vented to the atmosphere. The 49 states models just vent that Evap line to the atmosphere. They don't have the purge solenoid or carbon canister.

Numerous things could have happened:

It is possible your cap wasn't venting, caused a vacuum, and that's why you couldn't get your cap off... however, riding the bike, using gas, would only exacerbate the problem. It would build more vacuum, making it harder to remove the cap. Also if your cap is not venting (allowing gas into the tank) you would eventually have performance issues as the engine could/would starve for fuel if the vacuum was strong enough..

This cap vent condition could be temporary, intermittent, and it may never happen again. Or the vent in the cap is starting to fail, and could fail completely in the future.

If you have a CA model, you could have an issue with the purge solenoid that would build a positive pressure in the tank. That pressure would be alleviated by running the bike and using fuel. On a non-CA bike, you could have that Evap line plugged.

It's also possible that extra clicking to align that "Ride to Live" emblem has worn/damaged the cap in some mechanical way, that could cause over tightening.

If your cap is an aftermarket cap, not OEM w/an emblem, it could be due to many other things like its design, quality, etc, etc, etc.


This all leads me to the same course of action as the short answer, check the Evap line for being plugged/restricted and change the cap....

 

^^^ check the Evap line for being plugged/restricted ^^^ Good idea

P.S.
There's probably an extra gas cap on the pump at your local gas station

 

I carry extra gas caps in both my bikes, don't take up hardly any room. Didn't plan it that way, the situation just sort of evolved.

 

Thanks for the feedback, guys. I took the bike for a ride today and had no issues. The cap unscrewed fine when I got home. I spun the cap tight and clicked it for a few revolutions. When I unscrewed it again I looked at the bottom side of the cap and found some minor rust on the bottom of the cap and a little bit of crud on the surface of the tank around the fill hole. I cleaned the rust off with WD 40 and fine steel wool and the crud with a clean rag.
We're supposed to have rain here for the next 2 days so I'll take the console off and get to checking under there for any abnormalities. I'll keep y'all posted.

 

I didn't get to the gas cap like I intended. Still having no issues with it. I've ordered a new gas cap just in case. I've got another problem now so the gas cap problem will be on hold for a while, if not permanently. I'm going to start a new thread about my clutch.