In it's stock form, not really. You need to make significant changes to the muffler for that to happen. Exhaust flow needs to be better directed, header length between the cylinder and the muffler needs to change. outlet diameter generally needs to increase. Performance increases occur with $$ investment increases. That has never changed. However, some mufflers work better than others and finding the one muffler takes time and money unless someone has already done the leg work. I know that a J&A wrap around Pitts provides more power at a somewhat lower noise level than a Bisson of the same type on a 50-52cc engine, while an Abell muffler has a noise level similar to having no muffler while equalling Bisson Pitts performance. Other engines have different quirks. The right side dump mufflers do slightly better than wrap arounds.

The B&B requires more than a pipe size change. It also requires that the outside of the muffler be moved quite a distance farther away from the cylinder exhaust port and the muffler volume increase. The old B&B have the outside of the muffler where the exhaust is forced to make a 90 degree change of directions much too close to the exhaust port. Throw a rubber ball at a wall at a 90 degree angle and see where the ball goes. Directly back at the point of original release. So what you have is a reflector consisting of super heated gases. Think about what that's doing to your engine. Most general use mufflers have a similar problem but to a lesser extent.

The typical muffler was designed and created to re-direct exhaust gasses and to slightly lower noise levels. They weren't designed for performance enhancements. They do the job they were intended for but to obtain more from them is unrealistic. It's better to obtain an engine in a size that will provide the required power by itself than to buy an undersized engine and hoping additional power to meet the need be found in tricking the exhaust. It can often be done but at a weight and money penalty. The D 85 has changed that to some extent since it was designed around different parameters from the basic "industrial use" cylinder.

With only a few exceptions most of the engines on the market use cylinders with port designs originally intended for industrial use applications. DA, 3w, MVVS, RCS, and a couple others have been designed or modified around model use, the rest were not. To obtain additional performance from them takes some time and money.