Here's the inside of the muffler on my UK spec 440. Very restrictive.
Here's the 440 muffler on the left next to a 460 muffler. They are exactly the same size and the 460 muffler will even bolt onto the 440, but you can see the exhaust outlet on the 460 is set further back, so the chainbrake won't function on the 440.
Here's the inside of a 460 DP muffler I bought last year it Madsen's (p/n 1128 140 0616 I think). That's more like it.
Side on showing the DP next to the standard.
Here's the 440 muffler on the left next to a 460 muffler. They are exactly the same size and the 460 muffler will even bolt onto the 440, but you can see the exhaust outlet on the 460 is set further back, so the chainbrake won't function on the 440.
Here's the inside of a 460 DP muffler I bought last year it Madsen's (p/n 1128 140 0616 I think). That's more like it.
Side on showing the DP next to the standard.