How to Remove a Grizzly 660 Yamaha Exhaust Spark Arrestor

The Yamaha Grizzly 660 comes from the factory equipped with a spark arrestor. The spark arrestor restricts the decibel output of the vehicle to 85 dB, while also suppressing any sparks or flame that may result in a fire. Unfortunately, the spark arrestor also limits the exhaust air flow and therefore the horsepower of the vehicle. Removing the spark arrestor is often the first step to increasing the horsepower and improving the sound of the Grizzly 660. The job is simple and requires only one basic tool.

Things You'll Need

• Allen wrench set
• Work gloves

Instructions

1. Start the engine and let it idle for 45 seconds before turning it off. This will heat the pipe slightly, allowing you to unscrew the Allen bolts with ease.

2. Unscrew the three bolts on the tip of the exhaust canister with an Allen wrench.

3. Pull the exhaust tip out, using a pair of gloves to avoid any burns. The spark arrestor is attached to the exhaust tip and will slide out as one unit.

Tips & Warnings

• Some states require a spark arrestor on off-highway vehicles like the Yamaha 660. Check your state and local laws before permanently removing the spark arrestor.

References

• "Yamaha Grizzly 660 ATV, 2002-2008, Maintenance, Troubleshooting, Repair Manual"; Clymer; 2008