400ex bogs out when hitting water

[jrss13]

I picked up a 2000 400ex a month or two back. The last two times I've gone riding, it has been fairly wet and I've ran into problems with it bogging out and dying when going through water. The water isn't very deep, so I don't understand why its doing it. When it happened last week, I thought it was the airbox lid because the previous owner drilled some holes in the top of it. I went out and bought a stock lid and figured this would solve my problem. Well, today I ran into the same exact problem. At first, I thought perhaps some water was in my airbox, but when I took the lid off, it was completely dry.

It seems to me that it must be something electrical, perhaps my battery connection just getting wet.

I would try to start it right after it died, and it wouldn't go. After waiting about 3-5 minutes, it would then fire up and run perfectly.

Any ideas?

[norcalatver]

I had the same problem with my 400EX. I taped up every electrical connection, thought water was getting into the carb somehow, and it neded being the cdi. Its mounted just below the tank on the drivers side on the frame. I found out by accident because I changed to an MSD ignition when I did a rebuild. You might try some brushable rubber paint. they sell it at electrical wholesale houses. 3M makes it. You just brush it on, let it dry, and it makes an elastic water proof barrier. You might even try high temp silicone!

[400exrapes]

from my experience a month ago i had the excact same problem i thought it was my battery, no. Thought it was jetting, no. Its your cylinder my guess is youve got a bad piston or your cylinder needs to be rebuilt. Check your oil make sure its clean and check your filter, if its dirty drain the oil from the engine and oil tank and then put the new oil and oil filter in. run your quad and spray the quad with ur hose and if it bogs out rebuild it i had the same problem with mine a month and a half ago and now its rebuilt and im unstopable. My friends blaster, also rebuilt, also had the same problem. if you can rebuild it yourself do it cause shops will run you down 1000 bucks for the job

[400exrapes]

from my experience a month ago i had the excact same problem i thought it was my battery, no. Thought it was jetting, no. Its your cylinder my guess is youve got a bad piston or your cylinder needs to be rebuilt. Check your oil make sure its clean and check your filter, if its dirty drain the oil from the engine and oil tank and then put the new oil and oil filter in. run your quad and spray the quad with ur hose and if it bogs out rebuild it i had the same problem with mine a month and a half ago and now its rebuilt and im unstopable. My friends blaster, also rebuilt, also had the same problem. if you can rebuild it yourself do it cause shops will run you down 1000 bucks for the job

[serpent]

my quad have the same problem and i change the sprk plug cap and problem fixed try that

[2004exrider]

Originally posted by 400exrapes
from my experience a month ago i had the excact same problem i thought it was my battery, no. Thought it was jetting, no. Its your cylinder my guess is youve got a bad piston or your cylinder needs to be rebuilt. Check your oil make sure its clean and check your filter, if its dirty drain the oil from the engine and oil tank and then put the new oil and oil filter in. run your quad and spray the quad with ur hose and if it bogs out rebuild it i had the same problem with mine a month and a half ago and now its rebuilt and im unstopable. My friends blaster, also rebuilt, also had the same problem. if you can rebuild it yourself do it cause shops will run you down 1000 bucks for the job

Sorry but dont do that... my quad did the same thing before, do this
"I had the same problem with my 400EX. I taped up every electrical connection, thought water was getting into the carb somehow, and it neded being the cdi. Its mounted just below the tank on the drivers side on the frame. I found out by accident because I changed to an MSD ignition when I did a rebuild. You might try some brushable rubber paint. they sell it at electrical wholesale houses. 3M makes it. You just brush it on, let it dry, and it makes an elastic water proof barrier. You might even try high temp silicone!"

[1965 honda]

it should bog a little, water is resistance on the quad, its like going through real deep lite sand. haha

[400exrapes]

check ur battery first but then still i say its ur cylinder despite what everyone else says were not arguing im saying i have had two experiences with it and if its not battery have a shop look at it and you tell me what the problem is if its electrical

[Dill]

uhh, I highly doubt there is anything wrong with his cylinder.

[jrss13]

Thanks for the responses everyone. I'd be very surprised if it was the cylinder, because the engine was just rebuilt over the winter. It runs perfect and pulls really hard in every gear. I have a feeling that water is either getting into some electrical connection or somhow into the carb. I am going to try to seal up all the electrical connections first and see what happens.
Thanks for the responses.

[400exrapes]

if it was just rebuilt in the winter then i guess its electrical but its happened around here a bunchof times with cylinder for me and my friends

[MO-EX-RIDER]

if your hitting the water hard, you may be getting water in the spark plug hole causeing it to cut out?? mine does the same thing:devil:

[jrss13]

Yeah it happens when I hit the water somewhat hard. If I go really slow through water, it runs fine. I will check out the spark plug along with all electrical connections.
Thanks

[jrafter]

mine does the same thing and the parts guy at the dealer thought it might be the cold water hitting a hot motor and causing to cool off real fast.

im still looking at the coil