Boiling Gas?

I just bought a new '06 WR450. Last Sunday I took it out for the second time, it has a total of 40 miles on it. After riding about 10 miles of tight single track we stopped for a few minutes. When I tried to restart it started real hard and was dumping quite a bit of fuel out the overflow on the trail. I got it going, but it killed when I went over a bump. It was still dumping fuel when I tried to restart it so I opened the gas tank and it errupted fuel all over the place. The fuel was basically in a rolling boil and it continued to bubble for 10-20 minutes. The bike didn't seem extremely hot, overflow was about 3/4 full. After waiting 30 minutes or so I was able to get the bike started and ride out a mile or so to the trailhead with the fuel cap turned off a 1/4 turn. Is this common? Do I have a major problem going on? It's currently back with the dealer.

I have same bike w/more miles. I've been riding in this 90 degree heat wave and I have not experienced that. Good Luck!

I just bought a new '06 WR450. Last Sunday I took it out for the second time, it has a total of 40 miles on it. After riding about 10 miles of tight single track we stopped for a few minutes. When I tried to restart it started real hard and was dumping quite a bit of fuel out the overflow on the trail. I got it going, but it killed when I went over a bump. It was still dumping fuel when I tried to restart it so I opened the gas tank and it errupted fuel all over the place. The fuel was basically in a rolling boil and it continued to bubble for 10-20 minutes. The bike didn't seem extremely hot, overflow was about 3/4 full. After waiting 30 minutes or so I was able to get the bike started and ride out a mile or so to the trailhead with the fuel cap turned off a 1/4 turn. Is this common? Do I have a major problem going on? It's currently back with the dealer.

The WR's, because of the Communist Republic of California, are jetted REAL lean. It is probably even too lean for your altitude. I would most definitely buy a jet kit, or at least an adjustable needle. I think the jetting sticky is still in this forum. I'd check that out for a recommendation on your altitude.

M.

The WR's, because of the Communist Republic of California, are jetted REAL lean. It is probably even too lean for your altitude. I would most definitely buy a jet kit, or at least an adjustable needle. I think the jetting sticky is still in this forum. I'd check that out for a recommendation on your altitude.

M.

Should he buy new tires too??? Could that be it? The "fix-all" on this site seems to be to buy and install a jet kit, however, It sounds to me like you are getting a firsthand demonstration of Boyles Law... Pressure vs temperature within a fixed volume in this case. If your tank vent is blocked (thereby LOCKING the VOLUME of the tank) and it is hot outside when you stop the bike for a while (heat soak = Delta T +) then one must expect the tank pessure to rise. The fuel in the tank will then find the path of least resistance... through the carb.! Check your tank cap and vent tube for proper venting.

Something ain't right if your dumpin instead of burnin your precious fuel....I would take care of that problem first (float in carb bowl, vent block..?) then move on to boiling fuel, most like likely your header (lean Machine) cooking your fuel...

Let us know how it goes..

I've heard of this before on the WR's, like Monion said, if it's got standard jetting, jet her richer as the standard jets are way too lean and things get much hotter. Also like Airhose said, check your cap vent works properly.

I have seen a lot of cap check valve problems with the '06 WR's The valves aren't working properly and they are vapour locking the tanks, causing the bikes to stall and hard start. I haven't seen the boil over you described but if the tank is full and in the sun the fuel will continue to expand in the tank and may even push the fuel needle down and flood the carb. Try riding without the valve in the hose and see what happens. WR Dave :thumbsup:

that would scare me shitless gas exploding out of the gas tank

i would start running away lol

Nah mate, won't be blocked vent tube.

Bike will keep stopping and no fuel will get to the carby.

Ever heard of vapor lock???

I have seen a lot of cap check valve problems with the '06 WR's The valves aren't working properly and they are vapour locking the tanks, causing the bikes to stall and hard start.

:thumbsup:

well i read an article in twmx that u have to give ur gas extra protection from heat or it will boil. but that was pros with like high performance gasoline

that would scare me shitless gas exploding out of the gas tank

i would start running away lol

:thumbsup: Me too!

I gotta go with the "new tires" theory too. Maybe rotating the battery caps would help solve his problems LOL!

Sounds like the gas cap isn't venting at all; there should be no pressure in the gas tank at all. Your problem is similiar to leaving a full gas can (plastic) in the summer sunn for a few hours and then opening the vent. Lots of gas "spray" would happen; this would only apply to to the older non-self venting cans.

I have had the gas in my 03WR450 boiling when I was riding very slow...looking for my lost GYT-R exh. baffle. Got in the open and ran her fast for a few minutes to get airflowing and it stopped. This was on a 100+ day in the summer, Tucson,AZ.

I have had the same problem, IMS tank, hot temp, working the engine hard, slow pull up rocky hill, no air flow

gas will boil at about 157F depending on ethanol percentage

DON'T use a one way check valve, builds dangerous pressure in tank

Lowe's has 12"or 14'' wide furnace insulation, (foil and foam with a sticky back), you should help secure it with duct tape, cover the under side of the tank and very important to wrap your exhaust with CooL IT header wrap, you need to keep engine and exhaust heat out of the fuel and carb

this will fix your fuel boiling and the cooler fuel temp will run better

Haskell in Idaho, have a great ride

We have raced at Pikes Peak Co for the last 10 years. Our motorcycles, though roadracers would "boil" in the Co sun without the motors even running. Has more to do with how high up you are and less about the heat. The key here is the fact that the gas "boiled" for 10-20 min, the temp of the engine would have long cooled off by then. A better question might be what type of fule were you running?

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