muffler mod?

[manual]

Yes they are.
Also you have to adjust the carb.
Pull the limiter caps stright off sand down the stops and reinstall.

http://www.madsens1.com/mainmnu.htm
this is a great site for carb adjustments and other things

 

[enjoys cutting]

thanks for the site and the info,tomorrow should prove to be an interesting day.looking forward to the extra power and letting more heat out.