CRF50 Air Filter

PROJECT HONDA CRF50 IS THE THE ONLINE RESOURCE FOR HONDA CRF50 ENTHUSIASTS

PROJECT HONDA CRF50

 

TEXT AND IMAGES COPYRIGHT PROJECT CRF50 2008-2012

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IMPROVING ON THE STCOK HONDA CRF50 AIR FILTER

Our first effort at increasing performance centered around getting the motor to breathe a little better. The stock Honda CRF50’s air filter box has a tiny inlet that is very restrictive.


AIR FILTER: K&N ($25)

We decided to put a K&N air filter on. The first step is to remove the stock air box by removing all the screws holding it on. Also remove the crankcase vent hose (see section below about installing a new one). Gently remove the air box being careful not to get dirt in the carburetor.


Carefully clean around the carb inlet. Apply a little filter oil around the carb flange and slide on the new (oiled) filter. Tighten down the hose clamp snug enough so the filter doesn’t turn but not too tight. You will need K&N Filter Oil and Cleaner ($13) to maintain the filter.


This modification made a subtle but noticeable difference. The bike definitely accelerated a little better and revved a little quicker. When combined with our future pipe modifications (see pipe section) the difference was even bigger.


I recently bought a TWIN AIR Filter ($25), Oil and Cleaner as an option because it is what the factory Honda team uses. We haven’t tried it yet but we bring it to the track with us. Since it’s a foam filter it should be good for very wet conditions. NOTE: The Twin Air filter oil is green and will change the color of the dry filter.


CRANKCASE VENT/FILTER: The stock crankcase vent hose is attached to the stock air box. When you remove the air box you have to vent the crankcase somewhere else. To vent the crankcase use a piece of 3/8” inside diameter automotive fuel hose. Attach the hose to the crankcase using a small hose clamp (see photo).  Run the hose up through the left side engine mount and attach it to the seat stay with some cable ties. Run it up under the rear fender and cut it off near the rear of the fender. Install an Applied crankcase filter to the end with another small hose clamp. This setup keeps the filter in a pretty dry and dirt free location. Use a little filter oil on the foam insert and clean it after each ride. See photos below.

BREATHE A LITTLE EASIER

TWIN AIR CRF50 AIR FILTER

TWIN AIR
Filter Cleaner
($34)http://click.linksynergy.com/fs-bin/click?id=*hA8BfTTywE&offerid=139948.283683&type=2&subid=0http://click.linksynergy.com/fs-bin/click?id=*hA8BfTTywE&offerid=139948.283683&type=2&subid=0http://click.linksynergy.com/fs-bin/click?id=*hA8BfTTywE&offerid=139948.283683&type=2&subid=0http://click.linksynergy.com/fs-bin/click?id=*hA8BfTTywE&offerid=139948.283683&type=2&subid=0shapeimage_5_link_0shapeimage_5_link_1shapeimage_5_link_2

ENVIRONMENTALLY FRIENDLY

Hose attached to crankcase.

Hose attached to seat stay. Filter attached to end with clamp.

Hose coming up through the motor mount.