My boneyard MS260

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Stihldoc

Analog old guy in a digital world
Joined
Sep 15, 2005
Messages
181
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184
Location
Northern VA
Today I finished salvaging an early MS260 from my shop's pile of dead saws. This is one of the less desirable fixed high speed jet saws that seem to be scoring pistons from lean running on our area's E85 (15% Ethanol) fuel. I honed the cylinder and installed a new piston. The muffler cover got 2 extra 1/4" exhaust holes to supplement the existing 5/16" hole. The crankcase was pressure & vacuum tested. The saw was started and warmed up, it was taching about 15,600 RPM. Obviously a little fast. I replaced the original fixed jet (0.54mm) with a 0.58mm jet from a scrap MS290 carb. RPM now at 13,100 and saw has great power and no real noticable change in exhaust noise. I got out the calculator and found that a 0.58mm jet is 0.0228". I looked in my wire gauge drill set and found a 0.225" bit and drilled the original jet out to this new inside diameter. The saw now runs at 13,300 RPM and cuts great. This was a fun project and will hopefully soon be profitable when I sell the saw. My total investment was about $77.00- this included a Walbro K20-WAT carb. kit , a new plug, fuel filter, piston, and cylinder gasket. One boneyard saw down, probably about 10 or 12 to go...
 

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