hey all i may be wrong about this but i do recall reading somewhere that the standard 125 sp downpipe was restrictive and a better one was avalible or you could mod it to make it flow better. i think was weldind a edge then grinding it all out again ?? years since i had a 2t cheers steve
You can buy one from SIP that is bigger and made out of stainless steel. This is a topic showing the differences. http://www.scootershack.co.uk/viewtopic.php?f=20&t=3741
cheers i knew i dident dream it up lol are there any adcantages to having the exhaust port that large if all the other ports (172) are stock would have thought a loss in back pressure ever so ? cheers steve
the "restriction" in the exhaust is not a restriction... it sacrifices some peak power for torque.. this is part of the reason the stock pipe works really well at low rpm.. the rest of the exhaust prevents it from revving out so the bigger downpipe is a bit of a waste of time. you will gain some peak but probably loose more in torque (you WILL notice a loss in torque alot easier than a gain in hp) most id do is remove the exhaust gasget and take the lil lip out. maybe go up a couple mm in exhaust diameter... still, to actually do this properly would mean enlarging the entire port from the piston face to the exit. not a job for a beginner, or even semi skilled backyard mechanic. no such thing as free power. even if it costs you no money you pay for it somehow. (as in fuel, engine life, heat)
