How to Install a Pro Moto Billet Spark Arrestor on Honda CRF250R / CRF250RX (2018-2021)

The Pro Moto Billet PMB-01-1118 Spark Arrestor converts the stock dual mufflers on the 2018-2021 Honda CRF250R and CRF250RX into U.S.F.S. approved spark-arrested exhaust systems. This guide reformats the manufacturer instructions into a clean, easy-to-follow format for CRFsOnly.com customers.

⚠️ Before You Start

• Read all instructions completely before starting.
• This kit includes left and right side end cap bases and they must be installed on the correct side of the bike.
• You will not be able to reuse the stock end caps after installation.
• If you are not comfortable modifying exhaust components, have installation performed by a qualified technician.

🧰 Parts Included

• 1 Right Base
• 1 Left Base
• 2 Nozzles
• 2 Screens
• 4 M5 Bolts
• 18 Self-Tapping Screws

🛠️ Tools Required

• Drill
• 13/64" drill bit
• Hammer
• Center punch
• Allen wrenches
• Box knife or sharp knife
• Heat gun
• High-temp silicone sealant

🔧 Step-by-Step Installation

Step 1: Remove Side Panels and Mufflers

Remove the side panels and mufflers according to the OEM service procedure.

Step 2: Remove the Stock End Caps

Remove the 8 bolts on each muffler that hold the stock end caps in place. Pull the stock end caps and baffles out of both mufflers.

Step 3: Break the Factory Seal if Needed

If the stock end caps are difficult to remove, cut the existing sealant with a sharp knife and/or use a heat gun on the muffler canister sleeves to make removal easier. If needed, use locking pliers to grip the stock end cap.

Step 4: Clean the Mufflers

Before installing the new spark arrestors, remove any leftover sealant from inside the mufflers. Also make sure all old rivet material or debris is removed from the packing material inside the muffler canisters.

Step 5: Identify Left and Right Bases

The kit includes a right-side base and a left-side base. Install the correct base on the correct side of the bike:

• Right side = throttle side
• Left side = clutch side

Each base is labeled near the lower nozzle bolt location. Be sure the correct base goes on the correct muffler.

Step 6: Apply High-Temp RTV Silicone

Apply a small amount of high-temperature RTV silicone sealant around the stepped portion of the new spark arrestor base that fits into the muffler. This helps seal the base and prevent vibration.

Step 7: Install the First Spark Arrestor Base

Insert the new spark arrestor base into the muffler until the edge of the base meets the edge of the muffler. Drill one 13/64" hole at a time and install the self-tapping screws one by one. Each time you drill and install a screw, keep the base pushed tightly against the muffler. Using lubricant such as WD-40 on the self-tapping screws is recommended.

Step 8: Clean Excess Sealant

Wipe away any extra silicone sealant after the base is installed.

Step 9: Install the Screen and Nozzle

Insert the spark arrestor screen and nozzle. Install one short M5 bolt in the top hole and one long M5 bolt in the bottom hole.

Step 10: Repeat for the Other Side

Repeat the same installation process for the second muffler, making sure the correct left or right base is used.

Step 11: Reinstall the Exhaust System

Reinstall the mufflers, side panels, and seat.

🛠️ Maintenance & Inspection

• Inspect and clean the spark arrestor screens often.
• Recommended: check the screens every time you clean your air filter or change your oil.
• Remove mud and debris after riding to help maintain the finish.

⚠️ Important Safety Notice

A spark arrestor with holes in the screen will not function properly. Inspect the screens regularly and service or replace them immediately if damaged.

Shop CRF250R/RX Spark Arrestor

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