Stihl MS 660 Product Instruction Manual - Page 31

Chain Brake Releasing the chain brake English felling cut. The chain brake will operate only if it has been properly maintained and the hand guard has not been modified in any way. Check operation of chain brake Locking chain with chain brake Before starting work: Run engine at idle speed, engage the chain brake (push hand guard toward bar nose). Accelerate up to full throttle for no more than 3 seconds - the chain must not rotate. The hand guard must be free from dirt and move freely. Chain brake maintenance 143BA011 KN 143BA012 KN - in an emergency - when starting - at idling speed The chain is stopped and locked when the hand guard is pushed toward the bar nose by the left hand - or when brake is activated by inertia in certain kickback situations. N Pull the hand guard back toward the front handle. Always disengage chain brake before accelerating engine and before starting cutting work. The only exception to this rule is when you check operation of the chain brake. High revs with the chain brake engaged (chain locked) will quickly damage the powerhead and chain drive (clutch, chain brake). The chain brake is designed to be activated also by the inertia of the front hand guard if the forces are sufficiently high. The hand guard is accelerated toward the bar nose - even if your left hand is not behind the hand guard, e.g. during a The chain brake is subject to normal wear. It is necessary to have it serviced and maintained regularly by trained personnel, such as your STIHL servicing dealer, at the following intervals: Full-time usage: Part-time usage: Occasional usage: every 3 months every 6 months every 12 months MS 650, MS 660 29