How much restriction is too much?

GoldenMotor.com

blckwlfny1

New Member
Jul 14, 2010
128
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new york
I am running a morini clone. Ive fabbed a bit of an expansion chamber and placed a muffler (designed for a 100cc motor) on it. It still didn't have the kind of pickup that I wanted so I restricted the exhaust outlet.
My goal was to create more low end (7k for this motor) torque and I got it.
Besides just moving the powerband down and loosing some total HP, I am just wondering what else did I trade off?

Things like overeheating? blown heads, etc?
can someone tell me what to watch out for
Thanks