Rode about 5 miles yesterday in the bottoms (woods-shade) temp about 95 degrees. Every time I stopped I could hear a noise coming from my gas cap vent tube, open the gas cap and there were bubbles as if the gas was boiling. Fan worked throughout the ride but didn't come on every time I heard this noise. A friend had this problem with a Yamaha but I've never experienced it with my Hondas. Radiator clean, fluid levels good. Ideas?

 

Wouldn't worry to much if the quad was running good. Hot day + engine heat will make gas hot. JMO

 

I know my gas guage needle bounces around on my rubicon, sounding exactly like boiling gas. Shake your rubicon ever so slightly with your ear near the tank. Youll hear it. It gets worse as they age. mine is an 02.

However if you actually saw bubbles? I dont know what to say.

 

Hot motor plus vibration will cause gas to give off vapors.

Generally they will make a bubbling noise when gas condenses in the vent tube, and vapors end up perculating up through the condensed liquid.

If you were to measure the temp of the fuel in the tank, you would find it's not all that hot.

Anyway, don't worry about it, and enjoy the ride.

 

Mine's gurgled when hot since it was new, not a problem.

 

I heard on the Yamahas that it was actually a venting problem and not making the gas actually boil. Maybe it's something similar on the Rubicon. My friend has an 08 Rubicon that does that same thing.