Question about 2003 Yamaha WR 450 F

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Fuel overflow from carburator

2003WR - fuel overflow from carburator when not running. tank fuel tap closed doesnt stop problem.lost almost whole tank with tap closed. leaning bike on side for a while seem to help a bit. engin was missing a bit before this incident. bike was not ridden for some time.

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  • epb8 Apr 12, 2009

    Thank you very much, I have cleaned the float chamber and all is working at the moment . I will replace or get the fuel valve checked.

    Best Regards


  • Anonymous Mar 28, 2014

    the bike doesn't want to ref when I open the fuel on the tank



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You have a stuck float in the carb.  However, the fuel valve should have stopped the fuel flow.  so you need to rebuild the carbs and replace the fuel valve.

Posted on Apr 12, 2009


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Hard to start,runs few mins then stops, will not start back until its leaned over on its side , once up to temp runs ok.but now only runs few mins, will not stay running.

Hi please forgive the simple question. Is ther fuel in the tank? If there is the outlet of the tank could be blocked. Pull the fuel line off and turn fuel on you should see a steady flow if not remove tap and clean filter in tank. Otherwise check for kinked or damaged fuel lines. And drain the bowls on the carberator's. hope this helps Regards Jim...

Apr 15, 2015 | Motorcycles

1 Answer


if it leaks from the bottom it should mean the tank is overflowing, i.e. the fuel inlet seal leaks or is dirty. Remove it the carb, open it, clean everywhere, blow some air where the fuel was flowing. By pressing on the seal you should be able to stop the flow of air. If not, you know wich seal is faulty... Make sure everything is very clean inside. No water is acceptable at the bottom of the tank (it can happen.) Any liquid inside the floater is a bad sign; it must only contain air, otherwise it won't close the fuel inlet when the tank level is good... -> overflow! Good luck.

Aug 15, 2014 | Motorcycles

1 Answer

2002 Yamaha r1 bike starts but won't stay running

Hi, Anonymous and the usual suspects are:
1. Idle circuit and transfer ports clogged.
2. Air fuel mixture adjustment too lean.
3. Pilot jet clogged.
4. Faulty accelerator pump.
5. Float level too low.
6. Float bowl contaminated old fuel, water, dirt, rust, etc.
7. Float bowl vent or overflow tube clogged.
8. Fuel flow to carburetor restricted.
9. Intake manifold leak.
10. The gas cap is not venting properly or fuel tank venting system blocked.
11. Vacuum line from intake manifold to petcock broken, cracked, or not attached, carburetor vent line plugged.
12. Needle and seat stuck closed in the float bowl.
For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have nice a day.
07 R1 starts but doesnt stay running
Bike turns over but won stay running
OEM parts for Yamaha

Nov 11, 2013 | 2007 Yamaha YZF-R1

1 Answer

Carburator is over flowing

I have a 98 V star same thing happened carb float is stuck i drained mine tapped on them a few times and has ran fine after running cleaner with the first tank of gas

Jul 02, 2012 | 2001 Yamaha V Star 1100 Classic

1 Answer

Fuel over flows thru overflow tubes only when motor is running. motor off ignition on it stops.

Your gas tank petcock is diaphram operated.
there is a vacuum line coming off the intake, that goes straightb to the petcock.
when you turn the motor over a vacuum is created, pulling the petcock diaphram back and allowing fuel to flow to your carburetor. when you turn the motor off the vaumm is gone and the spring behind the diaphram pushes it closed and stops the fuel flow to the carbs.

Now the reason the carbs are overflowing is because the floats valves are not closing, in other words the floats are sticking.
Usually a good carb clean will cure the problem, especially for that year.
the older ones usually require new float valves/seats that are usually found in a good carb rebuild kit. You shouldn't need one.

If your really broke try tapping on the bowls of the carburetor lightly, while the engine is running, sometimes the vibration will vibrate a particle loose that may be holding open the float valve.
if it works then the fuel should stop overflowing while running.

if you know how to work on it, try this, with the engine off.
open the carburetor drain screws so that fuel will run out the carb. drain. flush out the carb.
get a container to catch the gasoline.
while fuel is flowing tap the carb bowls a few times then closed the drain screws.
clean up any spilled gasoline .
start your bike.see if they stop leaking and the floats are closing.
if it still leaks, you'll need the cleaning.

Happy Riding
Best Regards
Big Al

May 22, 2011 | 1997 Yamaha Royal Star XVZ 1300 A

1 Answer

Carburetta problem! Fuel continuosly flowing out of overflow hoses.

Your float is sticking... This moves a needle that opens and closes the fuel coming into the carburator. You can try to tap on the side of the carb with a wooden handle, and if that doesn't help, you need to get it cleaned out inside.

Apr 26, 2011 | 2003 Suzuki RM 125

1 Answer

My son owns a 2005 pw80 lately when he rides it, alot of gas runs out of the over flow tube what do i need to do to fix this problem

More than likely some grit or build-up is stopping the float bowl needle from stopping the fuel flow through the needle valve seat.

To test and clean, turn off fuel tap and drain fuel from carby via drain plug. Loosen carby manifold clamps and rotate carby enough to undo floatbowl. Return carby to level position and place a spill container underneath carby, turn fuel tap on and off (enough to allow small flow of fuel through open needle seat).

Now, gently hold up floatbowl with enough lift to close off needle valve seat and turn fuel tap on. If fuel still comes out you have a severe needle and seat problem requiring a replacement, if only a small weep of fuel is emitted it may just need a clean with a carby cleaning spray.

If no fuel comes out, your problem is the height adlustment of the floatbowl's level. Your engine is not using all the fuel that can be delivered and flows out the overflow outlet. The floatbowl level should be re-set incrementally to avoid leaning out your engine at high revs with too low a float level. To close off with a lower level you need to bend the small tab upwards.

The link below is for the same carby in exploded view format with all parts named. Cheers!

Sep 24, 2010 | Yamaha G5 Motorcycles

2 Answers

I HAVE A 2002 RM 250

You need to remove and clean the carbureator, the needle and seat are dirty and allowing the fuel to leak by and out the overflow. A good cleaning should fix the trouble.

Jul 25, 2010 | 2003 Suzuki RM 250

2 Answers

Fuel leaking into air box.

Probable best to take the carbs back, as there may be something clogging one of the float needle jets.
Although the bike is getting old, the floatlevels dont normally wear out of adjustment, as they have a neoprene end on one end of the needle and a spring loaded pin on the float end,
Unless there is damage to one of the floats.

Note ethanol in fuel can affect some carb parts like neoprene seals

Jun 04, 2010 | 1985 kawasaki ZL 900 A1 Eliminator

1 Answer

14" Ryobi petrol chainsaw will only run for 10 seconds

You are on the right track. Keep priming which indicates the fuel mixture is too lean to run. In other words the fuel line is partially clogged up. A drop of water on the gas tank would cause this problem. The fuel is fed on the suction basis. So clean up the fuel tank, (disassembly the carburator) reservoir, needle, float, offrice and fuel filter. A can of carburator cleaner (spray one) is a big help.

Jun 04, 2009 | Ryobi 18-inch Electric Chainsaw Chain Saws

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