Re: Well I just had to say this and see if anyone else has experienced this
I know you are not running a stock exhaust. I read that. I was writing in general terms for the general reader.
Here's a conceptual view of what I think you are experiencing. At low rpms BEFORE an expansion chamber can have full effect, it is possible that a straight larger diameter pipe will produce slightly more power. Especially detectable in a single speed bike. Now there is no way physically such a set-up will produce overall higher peak power within the most efficient powerband of a 2-stroke engine. In such a situation it would be basically trading off a nice torquey mid-high peaky on pipe powerband for a slightly more torque in an RPM range where the engine is not the happiest. This of course would not be a good choice for a bike with gearing where one could match that power band as needed with gears.