4 cycle muffler mod?

[Motodeficient]

Since I liked my refurb Ryobi 10532 chainsaw so much, and I needed a weedwacker, I ordered a refurb Ryobi 30cc 4 cycle straight shaft trimmer for $86 shipped. Is muffler modding bad on 4-cycles? Or should I just leave it alone?

 

[JasonBmac]

4 cycle engines can benefit from muffler mods, but likely the result won't be as dramatic as with a 2 cycle. This is because intake (actually transfer on 2 cycle) and exhaust are separate functions on a 4 cycle, but intimately related on the 2 cycle.....

4 cycle exhausts tend to look very small for the displacement, but often still function quite well... They're very different beasts.

J

 

[tdi-rick]

FWIW I pulled the spark screen on our Honda trimmer (spot welded on) and it is definitely louder and appears to rev a touch higher and hold it's revs better under load, but that could be a placebo effect too.