Boiling fuel---uh---YIKES!

A friend of mine from out of town took my WR for a trail ride today (I had to work and couldn't go--lame :D) As the story goes there was a section of the trail where it was fairly slow going and the bike died randomly. He heard a bubbling sound and noticed the fuel in the tank was actually boiling/bubbling. He went to remove the fuel cap and pressurized fuel spewed out everywhere. Figuring the one way check valve on the fuel cap was plugged they removed it and the bike ran good for the rest of the ride. On a side note once it died all the extra fuel pressure pushed fuel past the needle and flooded the engine.

Should I leave the check valve off and call it good or look into it further? I have an FMF header bomb (radiates heat like crazy) and one of those Ty Davis/IMS fuel tanks that comes extremely close to the header. I've never had this problem before but I'm certain this probably contributed to that... Good time to buy header wrap or a different tank? What do you think?

I'm just glad the bike didn't burst into flames with him on it! LOL :)

That has happened to me a few times while pathfinding through thick brush. I had one of those stubby breather valves on it. Once I put back the OEM valve and hose that goes down the steering tube, never boiled again. I could never keep that stubby one on anyway.

Yes, it's happened to a lot of us. Just run the hose without the one way valve. The valve is there to keep fuel from pouring out during a crash, and to appease the California Air Resourse Board.


Ha well thats good to hear I'm not the only one. Thanks for the reply's you guys I'll leave that vent off and call it good :)

I had just bought a brand new desert tank for my 426 and was about a half hour into the ride and I hear this wierd sound like water running. I opened up my gas cap and the fuel was spinning like it was going down a drain. It was the wierdest thing I've seen on a bike. All I could figure was that maybe the plastic was releasing some air bubbles because it was a new tank. I had my fuel boil over on a air cooled four wheeler one time and started throwing dirt on the motor because I thought it was going catch fire, pretty nerve racking, it just got to hot.

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