150cc stock exhaust drilling/mod with pictures

[gino pi]

i did mine, it came out good. i cut off the backfire screen area on the tube. i then cut down the total length of the first chamber, and welded it back together with no fiberglass packing inside. so its just a double chamber exhaust now. its lighter by alot and its still quiet. its good i think, and i think i need a larger jet now.