Has anyone figured out what causes the 400ex to almost die when you "charge" into water? Its weird, once you are in the water you can go in very deep without problem but charging into the water will almost stop the motor.

P.S. I race the entire GNCC series and have talked to a bunch of guys that run 400EX's. They ALL have the problem and no one has figured it out yet. Im 99% sure its not electrical and im 99% sure that the little water that gets into the airbox isnt causing the problem.

Don't try to solve this one unless you own a 400ex, its not a usuall waterproffing problem.

TeamVastnet: http://www.vastnet.net/teamvastnet
--John

 

That's a good question. The same thing happens to me on my 300EX. I hope that someone has the answer.

Chris "00" 300EX

 

John,

Boy, am I glad to hear you say that! I though it was only mine. I too race some GNCC's and hare scrambles. In the GNCC at Burr Oaks, every time I would go through that damn muddy creek, my ride would sputter and cough and nearly die. I lost a lot of ground because of it. In fact, I had just passed Mike Penland on that green monster of his when we hit the creek and, of course, my ride crapped out. Penland got back around me and nearly swamped me with the cruise-liner wake he was putting out! I was soaked and it took nearly half a lap for me to get back around him.

I was almost sure the problem was water getting into the carb but, as you mentioned, there was very little in my air box at the end of the race. Perhaps what little water does get into the box gets sucked straight in through the filter as it falls out of the intake tube. I just don't know. I hope someone has an answer for us.

Regards,

Dennis

 

Yea, that creek at bur oaks got me too. One the 3rd lap I almost stalled. I cant beleave how fast penland goes on that 4wd machine.....

--John

 

I know I don't have a 400EX but I have the same problem on my Big Bear. I thought it might have been 2 things. I thought it might have been the sparkplug cap, being hot and rapidly cooling might have sucked in a tiny bit of water which grounded it out for a couple seconds until the heat of the motor got it back up to temperture. And/or from having (guessing) that the engine is hot and the cold water splashing around it causes a sudden cool down, which what I thought might be partly seizeing but not enough to cause damage. I'm not sure, I just thought it might give an idea?

 

wow guys, my friend has a '97 Honda 300EX and he has the same problem. he can go through creeks if he eases into them, but if he plows into the water with in a few feet, he stalls instantly. it's funny/weird. what do you guys thing is going on? we think it's the spark plug gets wet or flooded. we dry it off and it starts up again. my 2-cents.

 

I think I may have a solution for you EX boys with the water problems. My friend had a 300EX with the same problem. We thought water could be getting in the carburetor vent hoses. I don't know for sure if this was the problem but by rerouting the carburetor vent and overflow hoses up near the airbox he solved the problem. Hope it works for you guys.

 

LT77,

I've heard that before as a potential fix but I've never tried it. I'll give it a shot and see if it helps. Thanks.

Dennis

 

DO NOT RE-ROUTE YOUR VENT HOSES TO YOUR AIRBOX! Although this worked on my friends 250R, it caused problems on my 400EX. When the bike is on a "wheelie" or on a steep hill the motor will cut out and suptter, and you will not be able to go past 1/4 throttle. For some reason those hoses need to leak gas in those situations, don't ask me why...

Trust me this drove ME NUTS! Don't do it on the 400EX.

--John

 

because on steep hills, the fuel in your carb tilts back, and allow's the float to drop thinking it is low on fuel.. causing way to much fuel to be in the carb and if it dosnt drain out the overflow it will make your engine run so rich it will seem like someone fliped choke on.-this is one of the 100's of reason's I cant wate for EFI
Joe