I have a 78 ciao, and I was when I removed the tail pipe (for a very short time) the speed of the ped increased from about 25 mph to 30. This seems like big enough of a gap that there is some restriction. I cleaned out the carbon from around the exaust port and on the front of a the pipe. I think that the exuast is clogged with carbon, does anyone else have an opinion, how can I resolve this?
Clogged exaust on Vespa Ciao
Re: Clogged exaust on Vespa Ciao
It's not unusual that a moped manufacturer would use a restrictive exhaust as part of a mandated (30mph?) top-speed-limiting strategy. I think that most (if not all) bikes would get a bit higher top speed by completely removing the exhaust pipe and running open exhaust.. (mine does it too).
My guess is it's just the nature of the two stroke engine that the it can rev a bit higher with an open exhaust port.
(This is not to say that just poking holes in a muffler would increase speed. Much more likely the bike will just be transformed into a equally slow but very loud cop-caller with a useless muffler.)
So, it's hard to say if your exhaust / muffler is actually carbon-fouled from that one top-speed result.
Most mufflers can be disassembled to some degree to allow for normal 2-stroke maintainance, like cleaning carbon.. check the owner's manual and examine the muffler for clues... but someone in here probably knows about disassembling the Ciao muffler. (also try an archive "search")
There's a lot of discussion about cleaning carbon and stuff in the forum's archives.. use the "Search" function. If a pipe's not chromed and looks don't matter and you can get away with it, baking the muffler to a red-heat in a fire will clean it.. But you get lots of smoke..
And carbon turns to carbon-di/mon/oxide only at very high temperature.. that thing's gotta be heat soaked red hot all the way to it's core.. My preference would be mechanical cleaning of some kind, just to make sure the exhaust's pathway is open.
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