Final update! Decomp block off was successful. No leaks no blowouts... yet. Took off the stock pipe and replaced with MLM G3 pipe, upjetted from 58 on the stock bing to 62. Moped would barely move, bogging down horribly. Ripped off the air box, and hit high 30’s on my first test run and haven’t REALLY tried to find the top speed yet. Because I desperately need new tires and the brakes are BAD.
Summary: the group diagnosis of a leaky decomp, and clogged exhaust was spot on. My g3 bogged down at 15 mph before; after following everyone’s advice my G3 with 9571 miles is now performing well beyond my expectations and running like a dream. I can’t Thank you guys enough for such awesome advice.