Stihl SR 450 Product Instruction Manual - Page 17

Harness Adjusting the harness Disconnecting harness from backplate 373BA003 KN 1 N Pull the ring (1) out of the slot. N Pull the ends of the straps downward to tighten the harness. N Adjust the harness so that the backplate fits snugly and securely against your back. Loosening the harness 373BA004 KN N Lift the tabs of the sliding adjusters. SR 430, SR 450 0002BA055 KN Fuel English This engine is certified to operate on unleaded gasoline and the STIHL twostroke engine oil at a mix ratio of 50:1. Your engine requires a mixture of highquality gasoline and quality two-stroke air cooled engine oil. Use mid-grade unleaded gasoline with a minimum octane rating of 89 (R+M/2). If the octane rating of the mid-grade gasoline in your area is lower, use premium unleaded fuel. Fuel with a lower octane rating may increase engine temperatures. This, in turn, increases the risk of piston seizure and damage to the engine. The chemical composition of the fuel is also important. Some fuel additives not only detrimentally affect elastomers (carburetor diaphragms, oil seals, fuel lines, etc.), but magnesium castings and catalytic converters as well. This could cause running problems or even damage the engine. For this reason STIHL recommends that you use only nationally recognized high-quality unleaded gasoline! Use only STIHL two-stroke engine oil or equivalent high-quality two-stroke engine oils that are designed for use only in air cooled two-cycle engines. We recommend STIHL 50:1 two-stroke engine oil since it is specially formulated for use in STIHL engines. Do not use BIA or TCW rated (twostroke water cooled) mix oils or other mix oils that state they are for use in both 15