restrictive exhaust

[claynine]

I am still curious about the tiny 1/2" tail pipe inside diameter of the Like 200i.  I am not an engineer, however the intake is choked down to some where over an inch and the throat of the butterfly valve is around and inch and a quarter.  So air can be sucked in through a relatively large hole then mixed with gasoline and into the combustion chamber where it is compressed.  It explodes and pushes the piston down with it's rapid expansion.  While it is still busy exploding ( although at the end) it has to get pushed through the exhaust valve and who knows what inside the muffler and inevitably through through this 1/2" tailpipe.  I wonder what the expansion ratio is compared to the air being sucked in through the air cleaner.  It seems logical to me that the exhaust should be at least as big as the intake..~1 1/4 inches.  Put your scooter on the center stand and hold your hand a ways away from the tail pipe.(it is HOT, so hold your hand a ways back) then feel the exhaust when you rev up the engine.  Has anybody did any mods to their muffler?  Please share as I am curious as to engine performance with less back pressure.

[91cavgt]

I have not done any mods to the exhaust, but I have priced complete exhaust systems for my Like.  I am debating to put a muffler on it since it will only help get to the top speed, but I doubt it will improve the top speed.  I am willing to bet money that the stock computer starts to retard ignition timing as you approach 60 mph, thus limiting top speed that way.  With that being said, I'll probably end up changing out the exhaust to a louder one, if for nothing else, so other people can hear me.  The stock exhaust is just too quiet. 


I have a few ideas going through my head in order to advance the timing a few degrees to see if that increases the top speed, as long as the engine is not already right at redline at 60 mph.