backofbeyond
ArboristSite Lurker
I bought a lightly used stihl ms390 yesterday for 200$. I got a wheel barrow thrown in with it! That is the factory bar so I figure it is lightly used. Compression is about 155psi but i was having trouble stabilizing the saw with the gauge in a vice so it could be slightly more? I took the muffler off tonight and drilled a hole in the area of the baffle with a 5/16 drill bit and opened the exhaust hole up a similar amount. I put the spark arrestor back in because i might use it in a small alaskan mill and i dont want fire hazard. I consider this a mild muffler modification, does anyone think it was not enough or too much? Ill retune the saw tomorrow. I took the limiter caps off tonight. ill post pics.