I have had this annoying rattle on my bike for a while now. Just figured it out to be the stock gas cap. It has a lot of play in it and is very loose. Is there a fix for this...

 

Yeah I honed in on that rattle the first day I rode my FB. Its kind of annoying so I guess I'll try another gas cap.

 

Put a hair tie around it.

 

turn it upside down and go around the edge with a screwdriver and hammer the edge tighter. Then screw it down until its snug. Don't keep tightening until it starts clicking

 

Replaced mine with a locking HD gas cap which seemed more snug than the stock one (rattle wasn't that noticeable but present.) Besides, I once had someone steal the fuel out of a bike once, so I won't put up with that again!

 

Check to see if your whole tank is tight too. The tank likes to rattle itself loose from the frame too. Sounds like the front end is coming apart when it does.

 

It is not the tank it definitely the gas cap...

 

My cap did the rattle too. Drove me nuts. It went away after awhile. Maybe it has something to do with pressure in the tank. I can't explain why it stopped all of a sudden, made no sense to me. It seemed to rattle more in cold weather.

I eventually replaced the caps with the flush fit ones. Maybe try a different cap.

 

Did that. It works

 

When I got a new one it rattled too.