During aggressive riding, the Yamaha Raptor 660's commonplace motor can, without trouble, outride most bikes in it's class. We really wanted to take advantage of the Raptor's motor and developed a Slip-On and Full System. We were able to see a 7% horse power gain with the Slip-On and 16% with the Full System, allowing for better top speed and "hook-up."

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Exhaust Series We Recommend:

Competition Series Developed for optimum performance, the Competition Series picks up great horsepower & gives you 3 different levels of power and sound in 1 exhaust. Learn More

Other Exhaust Series Available:

Performance Series	Quiet Race Series
The HMF Performance Series has a specially designed, unrestricted core that allows the exhaust to increase power evenly throughout the entire power curve. It also features the signature HMF sound with industry-leading end cap and color options, giving you a completely custom look. Learn More	The Quiet Race Series is designed for race vehicles and meets most sound regulations on the track while still delivering horse power gains throughout the power curve. When compared to the Sport Series exhaust with an HMF Quiet Core installed, the QRS delivers less dB. Learn More

Each HMF Exhaust:

Inlcudes a USFS Approved Spark Arrester. Includes a 2 Year Limited Manufacturer’s Warranty. Is made of high quality Aluminum, Stainless Steel, or Carbon Kevlar. Packed with high performance glass wool packing. Includes Installation Instructions. Manufactured in the U.S.A.

Don't Forget:

Whenever you add an after-market exhaust system to your machine, tuning your carburetor is, in most cases, an absolute necessity. The proper jets and EFI settings are extremely important for the performance and lifespan of your machine. Tuning Kits are available to ensure your machine runs at it's top performance and your HMF Warranty remains valid.

YouTube Videos: Raptor 660 (01-05)

HMF Recommended Jetting for Raptor 660 (01-05)

2001-2005: Slip on: 145 Left-150 Right (Mikuni Small Round)
2001-2005: Full System: 150 Left-155 Right (Mikuni Small Round)

• These settings were determined on our dyno at 900ft - 60°F
• Improper air fuel ratio can lead to engine and/or exhaust system damage not covered under warranty.

Tuning Kits Available:

Trail Kit	Track Kit	Competition Kit
The HMF Trail Kit includes the HMF EFI Optimizer and a Uni Foam Air Filter that will increase air flow and give your machine optimum performance and maximum efficiency. Learn More	The HMF Track Kit includes the HMF EFI Optimizer and a K&N Air Filter to increase the efficiency of your machine and run at an extremely high performance rate. Learn More	The HMF Competition Kit includes the HMF Basic Jet Kit, K&N Air Filter, and an Outerwears Pre Filter to give your machine and engine all around maximum performance. Learn More

Resources for Raptor 660 (01-05)

• Installation Instructions