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Old 12-08-2008, 05:42 PM
RLorange RLorange is offline
Motorized Bicycle Elite Member
Join Date: Jun 2008
Location: Australia
Posts: 127
Default Re: Expansion Chamber Questions

I have a similar ride home with a big hill. I have yet to try an expansion chamber muffler. I have the chamber ready but have had trouble finding someone to weld up a header pipe to the engine.

In the mean time the best simple mod I did that gave me at least 20% more power/torque at mid range revs was to lose the gasket joining the cyclinder to the bottom of the engine and use RPV silicone instead.

This does two things: Firstly it boostes compression a bit by shrinking the combustion chamber and secondly and more improtantly it lowers all of the ports thus changing the port timing for the better, my engine trucks up the same hill that it used to struggle on. Highly reccomended.

Also a high load up hills is not bad for a new engine as long as it is not too big a hill or you let the engine struggle to much. In fact it is good because the engine is at WOT with low revs forced upon it by the load this means plenty of richness and pressure to seat your rings.
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