Restore max power transfer, crisp clutch engagement, and reliable cutting force to your heavy-duty chainsaw with the Genuine OEM STIHL 3/8" 7-Tooth Spur Sprocket Drum Kit (Part #1122 640 2002). Designed as a solid, direct-fit replacement, this heavy-duty steel drum assembly swaps out worn, grooved, or heat-damaged drive components—stopping chain chatter, drive link burring, and clutch slippage instantly.
Why Choose Genuine OEM over Aftermarket? Commercial-grade 80cc to 90cc+ forestry saws subject drive components to extreme rotational stress and massive cutting torque. Cheap aftermarket spur drums frequently suffer from out-of-round machining, soft metal drive teeth that groove rapidly, and improper drum wall tolerances that cause premature clutch pad wear. STIHL OEM assemblies guarantee exact dynamic balance, precise needle bearing fitment, and long-lasting commercial durability.
What's Included
- (1) Heavy-Duty Clutch Drum with Integrated Fixed Spur Sprocket
- (1) Precision Clutch Washer
- (1) Factory E-Clip Retaining Ring
Key Features
- 100% Genuine OEM STIHL Quality: Built to exact factory specifications using high-density, heat-treated structural steel alloys for maximum service life under severe cutting loads.
- High-Torque 3/8" Pitch 7-Tooth Gearing: Optimized to deliver maximum pulling force and torque when driving long guide bars through dense hardwoods and large timber.
- Induction-Hardened Steel Teeth: Precision-ground spur teeth resist premature grooving to keep chain drive links meshing smoothly and safely.
- Integral One-Piece Drum Design: Combines the clutch drum and drive spur into a single rigid unit for simple, drop-in replacement during routine maintenance.
- Complete Replacement Hardware: Includes required drive line washer and retaining clip to ensure a fast, reliable installation.
Product Specifications & Compatibility
| Brand / Tier | STIHL® Genuine OEM Component Kit |
| Part Number / SKU | 1122 640 2002 (1122-640-2002 / 11226402002) |
| Chain Pitch / Teeth | 3/8" Standard Pitch | 7-Tooth (7T) Fixed Spur |
| System Design | One-Piece Clutch Drum with Integrated Fixed Drive Spur |
| Kit Contents | Clutch Drum w/ Fixed Spur Sprocket, Clutch Washer, E-Clip |
| Verified Compatible Models | • 064 Series: 064, 064 R, 064 RW • 066 Series: 066 M, 066 MR • MS 650 Series: MS 650 Magnum, MS 650-R Magnum • MS 660 Series: MS 660 Magnum, MS 660-R Magnum • MS 661 Series: MS 661 Magnum, MS 661-R Magnum, MS 661 C-M Magnum, MS 661 C-M R Magnum |
| Note | Needle bearing sold separately. Always inspect bearing during replacement. |