2001 Vstar 1100 Classic (sold), 2006 HD Electra Glide Ultra Classic
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13,905 Posts
An employee of mine just bought a bike. It's a ragged out Suzuki C50. Appears it spent a lot of time in Galveston and everything has surface rust on it. But he's proud of it. It's got some kind aftermarket exhaust that's super loud. Everytime he decelerations the popping almost sounds like a machine gun. So today after work I told him I would take a look. Has stock air box. Both header pipes were loose, tightened them up. Sprayed some brake cleaner around intake, no leaks. So I take the bike for a run around the block. There's some popping still, but not bad at all. He's all smiles now. So he takes it out and I could hear him and the exhaust was popping bad. So we go from almost no popping to machine gun popping. Only one difference, the rider. When I ride someone else's bike, I'm conservative on up and down shifting. He downshifts very early and slams the throttle shut at each shift. I had him try down shifting a little later and not slamming the throttle shut so quickly. He goes out and comes back and there's almost no popping. I then explain to him what's happening. When you slam the throttle shut with higher RPMs there's still enough vacuum to suck large amounts of fuel into the combustion chamber, to much to fully burn. That fuel rich mixture then goes into the exhaust, hitting the hot pipes and ignites causing the popping. This has been talked about here before but couldn't find it. There's been a few threads lately talking about popping with aftermarket exhaust. The popping is there with stoch exhaust, you just don't hear it. So if you put aftermarket exhaust on, have everything set right, maybe, just maybe, it's your driving style. How about a few of y'all that have some popping try down shifting a little later and don't close you throttle all the way and report back.
