why does my WR cut out in water?

Why does my 2000 WR400 cut out in water over the foot pegs?

It takes about 20 kicks to get going again.

the air intake is not taking in water.

It can be very frustrating when in the middle of a bog.

Could it be the carb breathers?


I've noticed my 2000 WR would run rough when I would run through large puddles. I thought it might be water around the plug but I'm not sure. I know my old toyota truck would do the same when I hit large puddles and I noticed when water pooled around the spark plugs the plugs would arc to the block causeing miss firings. Now, I don't know if it was a wire or water problem. I've always assumed it to be a water problem. In any case, I'm very interested in finding out how I can fix this problem. I hope someone else knows.


Look what I found in the Archive!!!!!

Im Going to try this at the weekend.

What you are experiencig is a breather resriction such as would happen with your gas tank if you were to plug off the vent tube on the gas cap.The gas won't flow out to the carb.The same happens when you ride into deep water that closes off air flow into the floatbowl.This allows the gas to flow from the floatbowl out though all the jets. Your WR400 has four breather tubes that run from a tee conector on both sides at the top back of the carberator and run down between the back of the engine and shock.Try pulling the tubes that come off the top of the tee and run them up under the seat along the top edge of the air filter box and tie them off to the frame.This fixed my problem on my yz400f. Dan Lombardy Grapeview Wa.



..and that works like a champ.

I spent a bunch of timeup to the footpegs in a puddle. Then I did the vent tee-thing and voila... river crossings are no problem.

Another point,

as far as that I am aware also when riding through deep water, if you do not keep the revs up then there is a chance of water being sucked up the oil vent pipe that runs from the top of the valve cover along the frame and out just below the cluch housing on the left hand side of the bike, causing MAJOR engine damage, so I have also extended this pipe into the air box,

P.S. its roughly 20mm in Dia.

T-venting the carb will solve this problem- here's a link to the pics of the T-vents on my 00 YZ 426F- T-vent Pics

I love happy endings... sniffle,sniffle....

TT is pretty cool.......

Cowboy, that is one dirty-ass air box. You should be ashamed! If you knew company was coming over it seems like you would have picked up the place. :)

My son rode his XR200 into a water hole and the whole bike was underwater. It stopped running too....

Rich- notice though that the dirt is only on the side where dirt doesn't matter- before the airboot :D I've got to have some evidence that I really do ride my bike :)


Thanks for the T vent idea! That seems to be the best solution I have seen.

The T-vents solved all my problems with stalling in deep water. I'm also working on T-venting the crankcase breather hose to the airbox and putting a valve on the bottom so that I can drain it when needed, but not have to worry about dirt and other unwanted crap getting sucked up the vent hose. I'll have some pics of that one too as soon as I get it done. PS the tubing I used for the T-vents was 5/16" (available at any hardware store) and the T fittings are vacuum line fittings that you can get any any decent auto parts store :)

"notice though that the dirt is only on the side where dirt doesn't matter- before the airboot"

I did notice that. Looks like your air filter is working overtime! :)

I, too have routed my carb vent tubes for deep water. But I didn't use a tee except on the float bowl vent tube. On the earlier model carbs, there are tees built into the carb so that four hoses are routed to the bottom of the bike. I took one hose from each tee and routed them to the airbox. I teed off the float bowl vent tube, routing one hose up and one down. On the newer carb models that's not necessary, but I think you still have four hoses, two on each side of the carb, routed to the bottom of the bike. You can route one hose from each side up to the airbox and it will accomplish the same thing as teeing off the lines. I've got a friend with an '01 model and that's what he did after he rode through deep water and had bad stalling problems while mine cruised right through. Now he can tackle deep water without stalling, too.

That's exactly what I did, I teed the upper line on each side of the carb. I didn't think it would be necessary to tee the float bowl line, so I didn't bother with that one. It has worked great for me, no more stalling in the middle of those colder than heck spring runoff creeks :D And- point taken, I'll clean out my airbox :)

Those are the only 2 vent you need to do?

You could do all four, I just didn't think it was necessary. You could probably get away with only doing one honestly. The point is to have a fresh air source for the carb when the tubes are under water. If you wanted, you could vent both tubes on one side, both upper tubes (like I did), both lower tubes, all the tubes, or any one of the four tubes. I chose to only do the two upper ones to keep it simple and to balance it out appearance wise. I've had my bike in water after the mod, and it has never stalled. What is worth noting here is that my bike is an 00- if you have an 01-02 (haven't looked close enough at an 03 carb yet) you will see a line that runs over the top of the carb and has what looks like a piece of electrical tape wrapped around it. If I had an 01-02, I would put the T here and only use 1.

The other two tubes are for fuel release. Running those upward can cause problem's in the float bowl area. I would not worry about those at all. Just make sure that the hose ends are cut in half at least 1/2 inch so they don't get clogged.

I went a slightly different route and installed the Carb vent system from PC Racing.


Bonzai :)

The PC racing kit does the same thing as what I did, but the PC racing kit costs $15 and two tee fittings and tubing was less than $5, and I didn't have to wait for it in the mail. Either way, it works. The PC kit may be more sano and professional looking, but I'm happy with the way mine turned out.

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