2003 WR450 Carb/Fuel Issue

I'm stumped... i was out for a ride, about a mile from home when my bike just quit. Good spark, no fuel. I have been riding several times with no issue. Fuel tank vent is working properly. I cracked the float bowl drain and nearly nothing came out. I opened the petcock with the fuel line off the carb, and the flow from the tank was unobstructed. I blew into the carb fuel inlet and could not blow through - keeping in mind that with the carb empty, the float should have been down, and the needle valve open. I pulled the float bowl, float, etc, and did not find any blockage or crud as I expected. Put everything together and it ran fine. Went for a ride last night and the same thing happened. I don't get it...

I know you check this but:

your tank's gas cap vent, if stock, is malfunctioning....you do have a tank vent issue i'm betting. I know you said the vent is working properly but it's an intermittent problem that causes this.

replace the vent thingy with long hose and route into steering stem.

if you have this happen again, crack open the tank cap to get running again.

That was one of the things I considered. I run a Scotts sub-mount and damper, so ditched the stock hose/valve in favor of one of those billet vent doohickies last season. Still doesn't explain why with no fuel in the float bowl I can't blow into the fuel inlet (even with compressed air).

Sounds like your needle valve is sticking. When you pulled the float out was the needle free? Pull it apart again and have a close look at the needle valve seat for any snags of brass, could be digging into needle and holding it closed.

Ok, it sounds like you got some crud blocking your needle valve inlet, instead of blowing INTO the carb, blow OUT, so take the carb out, take the bowl/float assy off, blow through from the bowl out into a rag placed over where the fuel line connects and see if a chunk ends up in the rag.

If your components look gummed soak them in carb/brake cleaner.

You might have lost one of your standpipes in the gastank which will then allow crud thorugh - it's happened to my bike where the main one came off, I ran out of gas, switched to reserve and was still out of gas because once it's off it allows the tank to drain to the reserve level without you knowing.

Look inside your tank when it's close to full, you might see the straw floating around.

Easy to glue back on - I used JB weld.

Well, I finally got it. Just returned from a little ride to Nova Scotia & had a chance to dig into the WR. I pulled the carb apart again and this time, found the neede valve nearly welded to the seat. After carefully removing it, I found that just enough corrosion had built up on the outer "ribs" of the valve to make it stick inside the brass seat. Strange that I had been running about a tank/week through it for several weeks before & stored it over the winter with the carb drained.

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