Oil pump unit as a replacement for STIHL petrol chainsaws MS660/MS650/066. Original part number: 1122-640-3201/3205

Is your large-displacement STIHL chainsaw exhibiting reduced cutting speed, chain slippage, or significant wear on the drive teeth? This is likely due to wear on the drive sprocket after prolonged use. This high-quality, integrated drive sprocket is specifically designed for professional chainsaws such as the STIHL MS660, MS661, MS650, and MS651 and features a 7-tooth configuration for use with 3/8" chains. Are you experiencing problems with your high-displacement STIHL chainsaw, such as insufficient, inadequate, or excessive lubrication, or poor lubrication of the guide bar and chain? This is likely due to an aging, clogged, or damaged oil pump. This high-quality oil pump unit is specifically designed for high-displacement chainsaws like the STIHL MS660, MS661, and MS650. It restores the normal function of the automatic lubrication system and effectively extends the service life of the guide bar and chain. How the oil pump works: The oil pump ensures a continuous and sufficient supply of lubricating oil from the oil reservoir to the guide bar grooves and the chain. At high chain speeds, an oil film forms, reducing friction and heat. A defective oil pump can directly damage the chain. This can This can lead to uneven wear of the guide bar and chain, or even damage to the guide bar. Key features: Authentic replica: Manufactured to the exact dimensions, pump volume, and mounting connection of the original oil pump, it fits your chainsaw perfectly. No adjustments are required for normal operation after installation. Precise clearance: The clearance between the piston and pump housing is precisely controlled. This ensures accurate oil flow with every cycle while preventing backflow and leakage. This avoids continuous oil dripping when the chainsaw is stationary. Oil-resistant seals: All seals are made of oil-resistant rubber that does not expand, contract, or age, even after prolonged immersion in oil. This ensures a reliable seal between the pump housing and the machine, eliminating any risk of oil leaks. Specifications: Part name: Oil pump / Automatic lubrication pump / Chain oil pump. Compatible models: STIHL 066, STIHL MS660, STIHL MS650, STIHL MS640, STIHL 064 (Partially compatible), STIHL 084, STIHL MS880 (not in inches, improves cutting performance). Drive sprocket function: The drive sprocket (gear) is a toothed disc mounted on the clutch that ensures power transmission from the clutch to the chain. Its condition directly affects chain efficiency and stability. A heavily worn drive sprocket can cause the chain to skip, resulting in inefficient cutting and even an increased risk of chain breakage. Key features: Optimized 7-tooth design: 7 teeth are the standard configuration for professional 70-90 cc chainsaws. Compared to sprockets with fewer teeth, a 7-tooth sprocket provides higher chain speed and improved cutting performance; compared to a sprocket with more teeth, it provides sufficient torque for cutting large-diameter wood. One-piece construction: This product features an integrated sprocket, providing a robust and reliable structure that requires no separate assembly. Compared to multi-piece designs, the one-piece construction Impact-resistant and therefore ideal for demanding professional forestry work. Wear-resistant hardened layer: The depth and hardness of the tooth surface hardening are strictly controlled. This ensures excellent wear resistance while maintaining core strength to prevent brittle fractures at the tooth tips. Specifications: Part name: Drive pulley/sprocket/drive wheel Number of teeth: 7 Tooth pitch: 3/8 inch (standard) Compatible chain type: Fits all STIHL chainsaw chains with a 3/8-inch pitch (e.g., 33RS, 33RM, 36RS, 36RM, etc.) Compatible models: STIHL 066, STIHL MS660, STIHL MS661, STIHL MS661 CM, STIHL MS650, STIHL MS651