View Single Post
Old 04-25-2011, 03:25 PM
jon.karak's Avatar
jon.karak jon.karak is offline
Motorized Bicycle Member
Join Date: Apr 2011
Location: U.S.A.
Posts: 38
Default Re: how to make an engine quieter/stealth

Any suggestions for quieting a 4-stroke? Part of the reason I bought a 4-stroke was because it is quieter than a 2-stroke. But even still I have to ride with earplugs at wide-open throttle.

I extended the pipe to the stock muffler, added a Supertrapp, and wrapped the whole exhaust with fiberglass header-wrap. My goal is to get my bike as quiet as one of those dainty little Vespa scooters. But for all my trouble, it doesn't seem to have improved things much at all.

My best guess it that the whole engine is radiating noise. I've never considered intake noise before. Does that effect 4-stroke engines too? Add to that the whine of the gear box, and I feel like I'm back to square one.

Has anyone ever fabricated a wrap-around enclosure? Something simple like a rectangular sheet of aluminum bent over the top. Maybe I could find a junk computer of about the right size and use the PC case? I imagine it could be lined with some kind of sound proofing (muffler packing?) and left open for airflow and the mechanicals.
Attached Images
File Type: jpg muffler.JPG (133.6 KB, 168 views)
2010 Soma Groove (21" frame) bicycle, Hua Sheng F142 49cc 4-stroke engine, GruBee Stage III Gear box, Sick Bike Parts shift kit, Alfine-8 Internal Gear Hub
Reply With Quote