Oil tank cap fix .
 

I've been having the usual issues with my 2004 XL1200 oil filler cap . It wouldn't turn the last 20 degrees unless I fitted a slightly smaller O ring but when I did this it leaked . So I went down to my HD dealership and bought a genuine O ring. I tried to fit the cap but I still couldn't get it to turn those last 20 degrees . What I then did was make a little sanding block and used it to slightly round off the angle on the spiral groove just where it transitions to the lock position. Result , turns all the way and doesn't leak !
https://cimg2.ibsrv.net/gimg/www.hdf...11c6107ee3.jpg

Thanks for sharing your solution.

I'm going to try that, thanks

Thanks for sharing.

Perhaps this is a tolerance problem as the two bikes I have here do not suffer like yours does.

It's not just mine , there are numerous references to this issue on this forum . I do agree though . I was in a Harley dealership the other day and every new bike that I tried had a cap that popped in and out without any bother. New ones do have ridges on though .

Another update.
 

I am delighted to report that after a 40 mile run there is not the slightest trace of oil dribbling from around the filler cap . So , rather than mess around with under sized O rings , if your filler cap gets too tight , just get a new genuine Harley Davidson O ring . The little modification I did just helps the tabs in the tank neck make the transition from spiral groove to horizontal groove . Works for me .

Thats exactly what I had to do to mine. I have osteo-arthritis in my hands and I don't have the strength I used to have, so it was getting impossible to open. I could just barely do it when I got the bike, but not at all now. So 2 days afo, I did the same thing, except with a small file. There is still a bit of effort required but easily doable by me now.

Had not looked it up on the forum, but good to know I was on the right track.

Thanks for posting.

Forgot to add, mine has the temp sensor cap on it.

Did you sand on the top, bottom or both?

Just the bottom where the clean spot is.
It the plastic deformed that much you should keep a new one as a spare in your bag just in case.

Yea just the bottom. Do it a little at a time. Don't want it too loose.