What is the general consensus on type of air filter I should be running. I ride on dusty mountain trails in Colorado and the dunes 2-3 times a year.

I currently have a K&N with Outerwear but just had the motor completely rebuilt due to "fine sand in the motor". I am now second guessing my decision to go with the K&N....is this the best filter for my area of riding? Is the K&N a great filter but I didn't clean it enough or properly oil it? Should I be using a foam filter instead? What are your experiences and opinions?

Thanks,
'99 400EX

 

You should use the K&N for the dunes, just keep it oiled. And use foam for the trails.

00 trx400ex - ac mudscreen front bumper, nacs headlight covers
86 trx200sx - powersport bandit 20 in rear tires

http://www.geocities.com/cory_14/

 

I run a Pro Design filter here in Az for protection aginst precisely the damage you mention. When removing the filter for cleaning, I never have seen the slightest trace of grit or sand at the intake to the carb. Altho PRO Design includes an over wrap foam filter with the primary one, I've never used it after a test ride with it installed. Until the monsoon arrived here we have been in a severe drought with the resultant clouds of dust and the filter never has passed any of it so far as I can tell. I would guess that the sand found in your engine was the result of of you trail riding rather than at the dunes. K&N filters seem to trap pure sand very well, but dust is merely airborne sand mixed with air. Of course the engine consumes the air but leaves the sand behind. The use of the prefilter should have prevented this but obviously it didn't. Maybe too little cleaning or too little oiling could have caused the problem. If Pro Design made a filter kit for Honda, I'd be the first to recommend it, but the last I heard they make only Yamaha filters or adapters.

 

I seriously doubt the K&N filter was at fault for your engine going south. It was most likely due to it not sealing correctly preventing the dust getting by the filter. I have ridden with a K&N since I bought my quad and will never change filter types. If you have the prefilter (outerwares) over a K&N nothing but air should be getting to your motor. Make sure you clean the K&N properly and oil it well... I over oil mine and then hang it up for a few days letting the excess drip off.

 

I run a K&N filter here in vegas where it is dusty all day and all night. Hot_shoe_cv is talking from experiance and so am I. Those of us who live out in the high desert now all about dust and sand.. My intake boot has never had a grain of sand in it due to the airfilter and i run my K&N without the airbox lid. I have heard of some inake boots on the Honda 400ex not sealing right to the airbox it self... It is only glued on... Run some silicon around it...