Why so loud?

[LI225Canada]

I recently removed the head and base gasket from my Lambretta motor with a Rapido Classic kit (Ancilolttie exhaust, 28mm Delly) which made the motor run properly. More power, smother operation, faster scoot, etc, etc...
Another benefit is that the motor is now much more quiet, why?
Keep in mind that it was very loud before I removed the gaskets. I would think that now that the motor has better compression and producing more power that it would make even more noise??? (Im not complaining. It was almost unbearable before.)
I cannot wrap my head around this, any insight as to why it was so loud?
The only thing I can think of is that it had something to do with the fact that the piston was not clearing the intake port all the way so the moving gasses were hitting the side of the piston making noise in some way.

[Daggs]

In order to remove the gaskets, you will have removed the exhaust. Perhaps when you replaced the exhaust, you sealed it properly?

[coaster]

In order to remove the gaskets, you will have removed the exhaust. Perhaps when you replaced the exhaust, you sealed it properly?

My thoughts too, most likely previously leaking from the stub/barrel joint or the slip joint. I think you would need to change the shape of the exhaust port to influence the sound/noise produced

[LI225Canada]

I never took the U-bent off. So maybe it was the slip joint.