05 Wr450f Pressure Build Up In Gas Tank?
Posted March 20, 2005 - 10:18 PM
Anybody have any clues?
Posted March 20, 2005 - 10:54 PM
What is the OTHER end of it connected to? Unless they've added a fuel return circuit as a part of the emissions equipment to make it green-stickered, there's no other source where it could become pressurized.
Last resort, pull the check valve and see if it still vents.
Posted March 20, 2005 - 11:30 PM
The other end goes to the steering stem, just like my WR400 and CR500! I took the hose off the tank cap, and it would allow air to pass in either direction (in or out).
The carb has the typical connections that my 2000 WR400 has.
I don't know why it is building pressure faster then the vent hose can release it, but my theory is that..... it is building pressue and is un-able to vent it, so it is forcing it to the carb through the fuel line, and then, being forced out the float bowl overflow line!
Posted March 20, 2005 - 11:51 PM
the other obvious things are to check the hose and blow it out.
I get bush wasp nests in thing like chainsaws exhausts and whipper snipper air in takes. etc
Posted March 20, 2005 - 11:54 PM
I am now out of my depth, good luck
Posted March 21, 2005 - 01:53 AM
I wonder if they put the check valve in the cap for the '05 for green compliance... dunno.
It does seem strange that it's happening, and it definitely should not be happening. I'd check with the dealer.
Posted March 21, 2005 - 08:10 AM
The only other variable in this problem is heat. It was around 80 degrees out (the hottest weather I have rid'n this bike in yet), and I was doing technical, tight hill climbs, and the bike overheated a couple of times.
THANKS FOR ALL THE INPUT
Posted March 21, 2005 - 09:34 AM
Posted March 21, 2005 - 10:01 AM
Posted March 21, 2005 - 05:34 PM
Heat from the radiators didn't even occur to me as a source of the pressure buildup. If that is the case, then I'll bet that the pressure problem got worse as the tank drained.
Simple solution? Do it the way it was done in 1978... remove the check valve, or replace the cap with one that does not have a valve built in if there's no valve inline.
Posted March 21, 2005 - 05:47 PM
I don't know whats going on here! I'm rid'n along and my bike starts stalling everytime I let of the throttle. Then when I stop, it starts pissing all the gas out of the hoses from the carb. I open the gas tank and it decompresses like it had 20lbs of air in it! Then, it runs great till it builds pressure up again, and starts the whole process over again.
Anybody have any clues?
Need to vent. The pressure is literally pushing the floats down by the inlet needle, thus, flooding the carb/engine and draining out the extra via the overflow hose. I'd check the gas gap and line for an obstruction.
Posted March 21, 2005 - 05:59 PM
Ya know... they really should go to a different design that is not pressure-dependent for proper operation.
The pressure is literally pushing the floats down by the inlet needle
Downstream valves open when overpressurized.
Upstream valves lock shut.
We try to use downstream valves in Scuba applications.... you can always breathe from a free-flowing regulator and make it safely to the surface... but for drysuit inflation, the valve is of neither design. Instead, the incoming air presses on the side of a hollow pin fitted with three o-rings. This pin has a solid area between the middle and bottom o-rings, and a perforation between the middle and top o-rings.
When the valve is depressed (or the float lowered in our case), the pin slips down so that the air inlet hits the pin on the perforated section, rather than the solid section.
These valves work fine under air pressures ranging from 80psi all the way up to 160psi. The only difference is how quickly the suit (or bowl) will fill when the valve is opened.
Posted March 23, 2005 - 09:14 PM
Posted March 23, 2005 - 09:19 PM
Posted March 24, 2005 - 06:45 AM
Posted March 24, 2005 - 07:30 AM
Posted March 24, 2005 - 08:11 AM
If it happens again, I too will dump the check-valve.