Need help! Stalling crossing deep streams on my WR450?

Anyone else stalling during or immediately after a stream crossing? I seem to require a lot of throttle (1/4 and up) when crossing deep streams, say 1/2 way up engine or higher. Once across, the bike will not idle for a few minutes and then it's fine. I've checked the airbox for water - no problem. I've also swamp proofed the engine breather hose by routing it into my airbox - not the cause since it was doing the same thing before I made the mod. I have not swamp proofed any of the carb vent hoses. I'm still having the off idle bog blues as well. Bike rips from 1/8 throttle on and I can wheely at 70 MPH but will die when going from no throttle to 1/2 or more quickly. If I roll it on, no problem. See my signature for details on jetting, etc. Any suggestions are MUCH appreciated! :)

You need to route some vent hoses into the airbox, either by taking the upper 2 of the 4 and routing them in (my suggestion) or buying the kit (some others swear by). See if that solves your water crossing issues.

i had the same thing happen to me in a 2 foot deep pool of water i think its because of the carb hoses or just water getting through the airfilter into the mixture and causing a bad ignition.. but the stock air intake is pretty protected from any water getting through so i would try routing the cables to the airbox that hsould fix it :):D

PC racing sells the carb vent kit that should solve your problem. I had the same problem on my 02' 426 and after installing the kit, no more problems. You could make your own with some tubing and plastic tees, but the kit is cheap, like $10-$15 only. Good luck


Everyone is correct. The 450 does not like having its vacuum circuit disrupted. You need to leave the vacuum hoses and T into them at both sides of the carb and vent it to the :thumbsup:top to the air box or beside the battery under the seat.

Thanks guys! Heading to my local aquarium shop for some hoses and tees. Don't know what I'd do without this forum! :)

I used said hoses and tee's from aquarium. I made the first one for my WR250 2-stroke (sorry) back in '94.I used a plastic film cannister (35mm film) at the end of the hoses. I stuck a piece of velcro (hook) on the cannister, and another (loop) on the inside of airbox. I cut a small peice of filter foam to fit inside of the cannister and put a little filter oil on it (a little excessive I know, I just had a lot of time on my hands that day). Now, when I change my filter, I also clean the filter in the can. The velcro makes it easy to install/remove for cleaning. Make sure you put the hooks on the can though, if you put them on the box, they can snag your filter when you are installing and removing it. Total, it cost me about a buck, and about 1/2 hour (I took my time), to do. I had most of the stuff laying around already. All I had to do was go to the pet store and buy the tees. Cheap, easy, and it works just as well on my WR450. :)


Did you route all hoses into one then into the air box or just the top two hoses into one then into air box. Any concerns on gas overflowing into air box? Anyone else want to describe their solution? :)

Motocrash that is an ingenious idea to build your own filter! Never heard that one before.

Gloft, FWIW, My first real bike was a 95 KDX, that bike had only 2 vent tubes so I T'd them. You need to have 2 tubes running down. Most modern dirtbikes have 4 vent tubes coming off the carb. With my last 5 bikes I have routed the 2 uppermost vent tubes, one on each side of carb, into the air box. I put lots of hours on a bike, cross lots of streams, and never had a problem. I like this cause the cost is $0. This was debated a few months back and some prefer to buy the kit and T the line an additional time, then you have 6 vent tubes. Either way should solve your water crossing issues.


What about gas from the carb flowing into your airbox after a fall? I'd hate to have a 6.5K bon fire :)

Thats why you take the top vents from each side of the carb. On each side of the carb there is a vent that comes straight out of the top, and a few mm below that is one that projects to the sides. It's really a built in T system, not much different than if you T the lines. In the old bikes you would T the 2 giving you 4. On the new bikes if you T you have 6, which I feel is over kill, others don't.

Leave the 2 projecting to the sides flowing down, so if you do burp some gas out the top if will go to these and flow down. While routing the other 2 into your airbox you have to go up with them higher than the carb so gas getting to the airbox would be very difficult if not impossible.

I was riding with a guy on a DRZ a few year ago and his bike kept dying in water crossings. DRZ's have only 2 vent hoses, so we did an on the trail repair and routed one up, left the other down. This was a week long ride with lots of stream crossings. He never had another problem. I did suggest he T his when he got back home.

Thanks for the heads up endurodog, I'll give it a try! :)

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