2004 KLR-650 Maintenance: Clean Air Filter


I am not a mechanic or a representative of any motorcycle or tool manufacturer or anything else official. This page is only my notes on doing this procedure myself. Although I believe what I have documented here is correct, I make no promises and you do this at your own risk.


The air filter on your bike needs to be inspected and cleaned for best engine performance, especially after riding in dirty, dusty, or wet conditions. My service manual specifies cleaning it every 5000 km.

Tools Required

  • Large and medium Phillips screwdrivers.
  • Long-nosed pliers.
  • Disposable vinyl gloves.

Materials Required

  • Kerosene, low flash-point solvent, or commercial air filter cleaner.
  • Warm running water.
  • Engine oil or commercial air filter oil.
  • Lithium grease.

Potential Difficulties

  • Possibility of tearing or puncturing the air filter foam by mishandling, in which case the foam will have to be replaced.  (No big deal – it’s not expensive.  But with care the existing foam can be reused many times, so be careful.)


You need about 2 hours for the cleaner and oil to set and the filter to dry, so start this task early, then do other maintenance while waiting.

First you must remove the right side fairing. Then:

Putting the bike on a rear stand makes this job much easier, by creating some extra ground clearance underneath and by levelling the bike for reading the oil level in the filler window.
The air filter is under a black cover on the right side of the bike, near where your knee would be when sitting on the bike. It’s circled in green here.
A single Phillips screw secures the cover. Remove this.
Grasp the back of the cover and pull it free of the gasket.
Then lift the cover away
With the cover off, the air filter is visible. It is held in place by a brass screw with a wing nut on the end.
It is awkward in there, and you may need to use long-nosed pliers to loosen the wing screw.
Then you can reach in with thumb and forefinger and back the wing screw out.
Remove the wing screw and set it aside.
Now work the air filter free of the housing, being careful not to catch and tear the foam.
Take the freed air filter away from the bike to a separate work area.
Use vinyl gloves while handling the air filter, as the foam will be sticky with oil. Carefully remove the plastic frame from inside the filter. I set it on a disposable piece of cardboard because the next steps are messy.
The foam filter must be cleaned with a low flash-point solvent. Kerosene can be used, or a commercial product like this K&N Air Filter Cleaner.
Following the directions on the bottle, we spray the foam thoroughly, inside and out, saturating it.

The instructions say to let the cleaner soak in for 10 minutes.

Then the foam is thoroughly rinsed under warm running water. Have the water flow through the foam from the clean side to the dirty side (i.e. inside to outside) so the soiled cleaner is carried out of the foam. (Sorry, I forgot to take a photo of the water rinse process.)

Gently squeeze most of the water out of the foam, then let it air dry. I suspend it on a wire, through the hole in the foam, in a sunny breezy spot. Then it takes about an hour to try.
Next the foam must be re-oiled. Engine oil can be used but a commercial product like this Spectro Air Filter Oil is very convenient.
It is an aerosol spray, and is coloured so you can easily see where it has been applied.
Apply oil to all sides, inside and out, and gently massage the foam to work it in evenly.
The instructions say to let the oil set for 20 minutes, when it will become quite tacky.
Wearing gloves, re-install the plastic frame inside the filter.
Carefully tuck the top of the frame into the lip in the foam.
Apply a thin layer of lithium grease to the edge of the foam, to aid the seal inside the bike.
Replace the foam element into the bike.
Make sure the element is positioned correctly and gently press it into place.
Replace the wing-screw through the filter.
Tighten the screw firmly.
Check that the gasket in a groove in the filter cover is in good condition, replacing it if necessary. Then reinstall the cover, tucking the front edge in first, then replacing and tightening the screw.
Congratulations! You have cleaned your air filter. Replace the side fairing and you are done.

The sticky aerosol air filter oil stays in the filter. However, if you use regular engine oil to soak the foam instead, some oil will drain out of the foam after installation, over the next few hours.

Stray fluid drains out of the air filter box and collects in the air filter overflow reservoir, shown circled in green here. It is behind the right-side front foot peg. A couple of hours after oiling the air filter, inspect this reservoir and, if there is any fluid in it, remove the drain plug (circled in red) and let it drain out, then replace the plug.


  1. Any suggestions on replacing the gasket in the cover? Mine is old and has disintegrated and am wondering of a easy solution?

  2. Great demo. Thanks,Senior Did as you did and she’s running great. Mucho Gusto! Viva El Rikardo!

  3. Thanks for the info. I cleaned my air filter but didn’t let it dry out completely before applying the oil. Now my bike backfires when releasing the throttle. Will do it over again today and see if the problem is solved.

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