Monster engine accidental performance increase

[Trip]

I'm running a Monster 49/52cc on a BMP kit. After riding it for a while I added Monster's velocity stack and breather. With some carb adjustment it seemed to add a bit of speed. I then decided to try their high performance exhaust. It seems to be more of a plain ol' exhaust pipe and muffler than an expansion chamber.


Well, on my third ride with the new exhaust the muffler canister broke off. I knew this for two reasons: It suddenly got very loud, and it got STRONG! I can't quite handle the noise level (it sounds like a chainsaw on meth), but the added power sure is nice.

Here's what I'm contemplating: I've got a few buddies with welders who could help me put the thing back together. However, when I look through the muffler I can't see daylight. I wonder how it would work to punch a hole straight through it and then weld it back on. If I could lose some of the straight pipe noise and keep some of the power I could live with the compromise.

Has anyone else played around with these motors to get gains in power?

 

[Skyliner70cc]

A free FLOWING (less restrictive) exhaust means no restriction resulting in a leaner mxiture setting creating more power. the power is usually not free because the closer you run an engine at the ideal stoichiometric ratio of fuel to air, the more heat (power too) you create that can be damaging to the engine. To ensure you aren't running too lean and hot, check your CHT with an IR temp guage and keep the engine between 250-300 deg F. If you don't mind shorter life span, you can go up to 350 deg F CHT (please use a castor oil blended 2 stroke oil) without worrying about sudden engine failure.

Have fun!