well here you go, in the first link (version 2) it tells how the peak RPM razed 300 RPM with the 12 extension. that's something new to me. and in the 2nd link, version 1, both use the same muffler.
version 2.
K&B Sportster 65 (2)
version 1,
http://sceptreflight.com/Model%20Eng...ster%2065.html
Last edited by the Wasp; 11-25-2021 at 06:56 PM.