marioweldinginc

2003 Honda 400EX Part throttle miss

12 posts in this topic

Was riding in PA on Sunday and after I would go through puddles I would get an intermittent part throttle miss in 2nd or 3rd gear only or would bog down a little then clear itself up. I emptied the airbox about 5 times. I have a K&n filter with no foam prefilter and an outerwears airbox lid. Would this setup be the cause or more electrical? After a while of just driving around the miss would go away.

I drove my quad up and down the street today after a wash and there was no miss.

Any ideas as to what to look for?

Edited by marioweldinginc

Share this post


Link to post
Share on other sites


I'm not to sure myself one thing I could think of is water getting in where your plug wire plugs on to your coil or spark plug. I feel it would mis in any gear not just 2nd or 3rd. If water was getting in your airbox & into your carb it would cause it to cutout as well. Their is a grease for electric connections you can put on all of you connections & it's for use where water may get too. You don't want water getting in your airbox Most airboxes have a drain in the bottom check yours and make sure it's not stopped up. If you had to empty it 5 ties how much water was getting in.

Edited by hangingon

Share this post


Link to post
Share on other sites

Im not sure how much water was getting in but I pulled the drain 5 times to see if there was water in it and all 5 times water came out. It was pouring rain so i didnt want to take apart the quad on the trails.

The K&N filter goes almost all the way to the bottom of the box thats why I thought it was water going into the engine. I also thought because it was jetted for Long Island (about 20ft above sea level), that maybe the carb was off? No backfire or anything. Im not sure how high above sea level St. Clair PA is and would that make a difference?

I will put dielectric grease on every connector I can find then

Share this post


Link to post
Share on other sites
I'm not to sure myself one thing I could think of is water getting in where your plug wire plugs on to your coil or spark plug. I feel it would mis in any gear not just 2nd or 3rd. If water was getting in your airbox & into your carb it would cause it to cutout as well. Their is a grease for electric connections you can put on all of you connections & it's for use where water may get too. You don't want water getting in your airbox Most airboxes have a drain in the bottom check yours and make sure it's not stopped up. If you had to empty it 5 ties how much water was getting in.

I`d say water is your problem !! I`m running K&N filters with outerwears and haven`t had a problem !! But I avoid huge water holes :laugh:

Share this post


Link to post
Share on other sites

I think elevation would slow it down but not skip. The higher you get the harder to breath same with a motor so if you cut off some of the breathing it robs power from the motor.

Share this post


Link to post
Share on other sites

Yeah, I'd rule out the moisture once again. Then go from there. Good luck and keep us posted!

Share this post


Link to post
Share on other sites
I think elevation would slow it down but not skip. The higher you get the harder to breath same with a motor so if you cut off some of the breathing it robs power from the motor.

True but here I live at 5500` but most of my riding is at 8500` and above only thing I notice is loss of power:yes: I think his problem is water 400ex is not a water craft !!:laugh:

Share this post


Link to post
Share on other sites

Id drive a corvette through 3 ft of water just to see if I could do it. Then post why does the car sputter and stall :)

Share this post


Link to post
Share on other sites

Conclusion - drawing in water through open airbox. When its sunny and dry with no puddles, nary a miss. first good puddle it has a slight miss then clears out.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now