The 2025 Honda CRF motocross bikes come with a removable back fire screen fitted behind the air filter. These screens are normally moulded in place and require cutting out but the CRF’s screen is now fitted in place by a screw making them easy to remove. Removing these screens helps the engine breathe easier and makes the engine more responsive.

#1

To remove the screen, place the bike on a solid stand and start by removing the side number plate. To do so, remove the 8mm bolt securing the side number plate and then slide the plate towards the rear of the motorcycle to pop it loose.

#2

Next remove the air box cover by removing the 8mm securing bolt and then folding the cover back and away from the motorcycle.

#3

Next you will need to remove the air filter by removing the securing clip at the top of the air filter. Then pull the air filter out of the air box and set it aside.

#4

Now that the air filter is removed you will see the Phillips head screw securing the back fire screen. Remove this screw and then pull the screen out of the air box and discard.

#5

Now refit the air filter by placing it in the bottom location pins and then securing the top mounting clip.

#6

Refit the air box cover and secure the 8mm mounting bolt and then refit and secure the side number plate using the 8mm number plate mounting bolt.

Dos

  • Check that the air filter is secured correctly and is sealed around all sides of the filter.
  • Keep the screen somewhere safe in case you ever need to refit it.
  • Make sure the securing pin on the air filter is fitted correctly and tight.

Don’ts

  • Drop the screen mounting screw in the air box.
  • Over tighten any mounting screws.
  • Force any plastic pins or clips as they will break.

Tools:

8mm T-bar, Phillips head screw driver

Warning:

If your air filter is not fitted correctly then your engine will suck in dust and dirt which can cause significant engine wear and damage.

What is a back fire screen?

A back fire screen is fitted in the airbox between the throttle body or carburettor and the air filter. The purpose of it is to stop any flames or sparks coming from the engine and igniting the air filter if the engine was to backfire. It is very uncommon for modern fuel injected engines to backfire unless there is a major engine or electrical malfunction. In race bikes this screen is removed to allow the engine to breathe better and produce more power but there is a slight risk that if the engine was to backfire then the air filter could catch fire. There are however aftermarket air filters on the market with a layer of flame retardant foam on the inside of the air filter to minimise this risk.