WR 400 Drinks water.

After dumping my trusty steed into Belt Creek, Mt. The old girl refuses to kick over. We drained all the h2o out, pulled the plug,turned the bike over to drain the head. But alas we ended up pulling the bike out the awesome single track to a trailhead. After getting back home and draining the crank case, no water, it still refuses to budge.

Any suggestions? The engine was idling as it went into the drink.

Steps to try:

Pull plug and coil out of the head and try to kick it over and check for spark.

Clean the carb and make sure you gas is clean.

Clean and install air filter.

Check that the exhaust pipe is clear and unobstructed.

If that fails you have to do more drastic inspection of the valve train to make sure timing and cams are in sync.

Good luck with it. :thumbsup:

If she sucked in a lung full of water on the way under she may have bent the connecting rod due to hydraulic lock and jammed the piston in the cylinder. There's probably a chance that cold water hitting a hot piston could crack it. Then again she may just have a frog stuck in her throat. :thumbsup:

Keep in mind that restarting may not have been the cause. The engine could have locked as it went under spinning. I do a bit of watercross on my sled and bike and have sunk the sled a few times. The sled takes about 30 seconds to sink so there's plenty of time to shut down the engine before it sucks in water. Bikes are a different story, they go down like a bat inta hell. When I run the bike across water I keep my finger poised over the decomp lever. If you hit and hold the killswitch, the engine could still be spinning as it goes under and break things. If you hold the decomp as it goes under you still kill the engine and you also create a bit of pressure release which may save the rod. Some of you may be thinking that you could bend a valve, but wouldn't that be better than a rod, piston and cylinder? This also depends on 2 things,1 that you have the presence of mind to grab the lever, and 2 that you still have the bars in your hands. Now keep in mind that I'm just making this up as I go along, I could be wrong. I haven't sunk the bike yet but I'm always ready. If you look closely at my left hand in this pic, and if the hand guard wasn't in the way, you'd see my finger ready for action. I've even been thinking of hooking up a tether system for water runs, with a bungee trying to pull in the decomp, a block between the lever and the bar, and a tether line tied to the block. Then, in a perfect world, if I get disconnected from the bike in the water the tether pops the block and the decomp goes in letting the bike sink safely to the bottom. In the real world the block would probably vibrate out and kill the engine halfway across an otherwise perfect run. :thumbsup:


This would be a good question for a motor/engine tuner. If my bike is spinning at for example 5,000 rpm that means the motor is turning 8.33 times a second. A second is a long time in engine speak and I am sure you are turning some serious RPM in the photo of you riding across water. Divide that second by four and you get roughly 2 engine revolutions every .25 seconds. I would be curious if doing the mod you describe would work.

Kinda like hearing something thrashing in your engine and you hit the kill switch and the damage is still done due to the engine being a mass and won't stop like a light switch. In my case I hit a rock in a slow water crossing and started to fall to the throttle side which made the engine run faster and it dumped into the creek/river. Freak accident and all my foursmokes has all the free mods. for water crossings etc... I sank my WR250F numerous times and no problems. By the way, They had to pass a law in Montana against snowmobiles on bodies of water because of people drowning and suing the state because no one told them it is illegal. I did not know of the Nunavut nation and curious if rocks grow in the Artic Circle and how many words for SNOW do you really have? Montana riding season looks pretty damn good compared to your latitude dude. :thumbsup:

My theory on the decomp lever is the engine may still spin submerged without hydraulic locking. The open valve may let out enough water to keep the con rod straight. I don't know how far the valve is held open but I guess there is a chance it could kiss the piston.

As for sled on water laws, there are none. There are barely any normal laws here let alone off the wall stuff like that.

I wear a 3/8 wet suit for sled watercross. It's super buoyant and keeps me from freezing. On the bike I wear a PFD.

Rocks, we have a bumper crop....


I don't know how many words for snow we have, but I have plenty that I use when I get stuck. :thumbsup:


I appreciate all the suggestions! After getting it back home I drained the crank case, a bit of trout stream in there! Drained my carb, lot's o'creek in that as well. Took out the plug and tipped her up on her back, no water there. Still, no go on the kicker. So being the smart redneck, I took it into a trusty mechanic to work out the details. He basically said that it could be anything, from the piston to the valves. Though he has never heard of a piston sieze from a "idling" bike into water.

The day after I dumped my bike I ran "gas" shuttle on buddies 105 mile trail ride. They had a few more names to call me for running the gas shuttle, but you shoulda heard what they called the guy that put his bike in the back of my truck at the meeting point!

Thanks for the tips and I will let you know what happened to the motor. P.S. should I bore it out for that extra juice as I roost past my buddy (as always) on his crf450?

P.S. Frostbite needs a trials bike, and land that has plush single track. Nice photo's though. Crazy.

Though I have heard that if you hit your decompression lever when the bike is running you can bend the valves?

Though I have heard that if you hit your decompression lever when the bike is running you can bend the valves?

Nope. Wrong. All the decomp thing does is hold a valve slightly open by pressing on the corner of the valve bucket. You run the engine through its revolutions with the lever depressed to deflood it etc. Same deal when its running, only its spining faster. If they were interfernce valves then you wouldnt have a decomp lever working in this way.

Use it to stall the engine and also start. Roll downhill, decompress, let it go and ride away. No more kicking !

I'm not clear on whether the kick starter moves thru it's stroke easily. Does it just not want to start or you can't get the motor to turn over?

If it just doesn't want to start, take a look at the position of the cam lobes when the TDC mark is up on the flywheel. The exhaust lobes should be pointed at about 9:30 and the intake lobes at about 2:30.

If the rod is bent, the piston won't be even in the cylinder left to right. Use a long piece of some 50/50 solder and stick down the plug hole to see if it gets squeezed more on one side than the other of the bore. You'd be checking the squish area of the bore so the solder needs to go to the edge of the bore.


Well the Dr. sez that he has never seen a bent rod after having water in the exhaust pipe, but alas the rod is bent and now the overhaul begins. Quite amazing that the rod would bend after a small dunking! The mechanic has only witnessed that after boring the engine to a 420. Apperantly the factory rod is micro-adjusted too a 400. Do NOT rely on the stock rod if you are boring out the 400!

The old girl should be running by next week.

Washougal is the 1st, see you there!

P.S. Always put your thumb on the kill switch when crossing a water hazard. Take it from my checkbook! $*$*%!

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