Products Description
MS661 Brake Hand Guard – Chain Brake Activation Lever
Essential Safety Component for STIHL MS661, MS651 & MS661C
The brake hand guard (also known as the front hand guard or chain brake lever) is a critical safety component on the STIHL MS661 chainsaw. It serves two essential functions: protecting the operator's left hand from projecting branches and contact with the saw chain, and acting as the activation lever for the chain brake system .
Technical Profiles & Materials
OEM-Spec Replacement Fitment – Replaces STIHL OEM part number 1144 790 9100 . Fits STIHL MS661, MS661C, MS661 C-M, and MS651 chainsaws .
Dual Safety Function – Protects the operator's left hand from projecting branches and chain contact while serving as the activation lever for the chain brake system .
Chain Brake Activation – The guard is designed to be pushed forward to manually engage the chain brake (locking the chain), and pulled back toward the handle to disengage. An audible click confirms when the guard reaches the locked or unlocked position .
Quick Installation – Designed for straightforward replacement with basic tools. The guard and brake lever are accessed by removing the E-clip and pulling them off the pivot pins together .
Available as OEM or Aftermarket – Genuine STIHL parts and quality aftermarket alternatives are available. Aftermarket options offer cost-effective replacement solutions for routine maintenance .
Technical Specifications
| # | Parameter | Specification |
|---|---|---|
| 1 | OEM Part No. | 1144 790 9100 |
| 2 | Compatible Models | STIHL MS661, MS661C, MS661 C-M, MS651 |
| 3 | Function | Front hand guard / Chain brake activation lever |
| 4 | Material | High-strength plastic / Durable polymer |
| 5 | Related Components | Works with brake lever, cam lever, E-clip, and brake spring |
| 6 | Service Note | Lubricate brake lever, cam lever, and hand guard slot with STIHL grease during installation |
Products Application
Safety System Restoration
Direct replacement when the original hand guard is cracked, broken, or fails to engage properly. A damaged guard compromises the chain brake's ability to activate during a kickback event and must be replaced immediately to maintain safety .
Chain Brake Repair & Servicing
The hand guard works in conjunction with the brake lever, cam lever, E-clip, and brake spring. When replacing the guard, inspect these related components for wear, and lubricate the contact points with STIHL grease during reassembly . The cam lever defines the locked position of the hand guard .
Preventative Maintenance for Professional Saws
For professional arborists and forestry workers using MS661/MS651 saws, regular inspection of the brake hand guard is recommended. Replacing a worn guard proactively ensures the chain brake mechanism functions correctly in critical safety situations.
Quality and Craftsmanship Details
Products Package
About Us
As a premier garden machinery parts supplier, Jiaxing Norsun Trading Co., Ltd. bridges global distributors with over 100 vetted China manufacturers. We streamline your B2B supply chain through strict quality control, flexible production, and factory-direct wholesale pricing. Partner with us for reliable, high-volume sourcing of precision-engineered outdoor power equipment components.
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FAQ
Q: How do I confirm this hand guard fits my MS661?
A: Check your chainsaw model number on the housing. This guard fits STIHL MS661, MS661C, MS661 C-M, and MS651 models. It replaces OEM part number 1144 790 9100 . For MS661 C-M variants, the same guard is used .
Q: How do I manually engage and disengage the chain brake?
A: Push the front hand guard away from the front handle (forward toward the bar) to engage the chain brake – you will hear an audible click. Pull the guard back toward the front handle to disengage . High revs with the chain brake engaged will quickly damage the clutch and chain brake .
Q: How do I install a new brake hand guard?
A: Remove the E-clip, then pull the hand guard and brake lever off the pivot pins together . Lubricate the brake lever, cam lever, and hand guard slot with STIHL grease, then push the guard and brake lever onto the pivot pins and fit the E-clip .
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