Seem like they would have had the expansion chamber further toward the engine like a motocross bike.Exhaust is the easiest hop up to make use of . I found these for the under 35 cc saws . Off RC cars . I ordered a couple just to have around . I love the small saws .
View attachment 631201
They are 8" long by 3" wide with the CNC cut swivel mount . Adapt it ! Now Im looking at bigger carb jets .
Steve