Does changing the size of the exhaust pipe, or the silencer in case of bikes result in any drop of fuel efficiency and/or power of the bike?

satguru

I remember people doing this, and I think the bore affects things the most, and power, but especially noise levels are both affected. But I think power can be increased as well as lost, hence those posh exhaust conversions with steel boxes. They aren't there for appearance only, as are superior and used on cars as well. It's been a long time since I was on that scene but that's what I remember they were for. Apr 21 06, 9:27 AM

xfacilitatorx

Improved exhaust flow can yield an increase in power. The easier that air/exhaust can flow the less resistance on the piston and the quicker the cycle or stroke can happen thusly yielding higher HP. But........Not enough "back pressure" or resistance toward the piston and things can go seriously amuck. Spin-out and damage to connecting rods and crank bearings often occurs. Valves can also be damaged from lack of resistive pressure. This site explains a portion of what I have written. http://auto.howstuffworks.com/question172.htm http://auto.howstuffworks.com/question172.htm This site tells about ways to increase HP and efficiency. http://auto.howstuffworks.com/question395.htm Apr 21 06, 12:03 PM