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All the pipes sold for these engines are made for pocketbike racers, not for low rpm single speed street bikes. A racing pipe only enhances top rpm power (if the header length is correct for the engine specs and top rpm). My latest design enhances low rpm power without detracting from top rpm power. I´m giving the design away here. Pipes arent too hard to make. Just takes patience and determination. The sheet metal ideally should be steel of .7mm thickness. Someone told me that the steel from a water heater is just about right. If you buy a sheet then it should be the kind that rusts since it is easiest to weld. You can use tin snips to cut the pieces out. A computer program can printout the pieces on paper that you can use as patterns. I use a rubber mallet, pliers, and needle nose pliers to bend the pieces. I use a bicycle fork to bend the pieces onto by hammering the piece while it rests on the fork. Other metal cylinders of various diameters can also be used. You will need to find someone with an oxyacetylene welder to weld it together. Emphasis to them that it needs to be lightly welded so that little "slag" extends inside the pipe. For an upswept pipe you can cut off the std muffler for the first section. Second section is only the curved header pipe from a standard muffler, 6.5" long (centerline). This sets the correct tuned distance for around 6000 rpm max. For a muffler you can make a cylinder with removable metal scouring pads inside it. Just put small holes in the end of it. Less holes is less noise.
There is no feeling equal to having your own handmade expansion chamber on your pipe and feeling the difference it makes. I knew nothing about making them but I just dived in and did it. Anyone with one brain and two hands can make one.
I used my newly created Excel files to come up with these dimensions. Click here to read about how expansion chambers work and how extending the last cone (the baffle) extends the pipes powerband.
enjoy
There is no feeling equal to having your own handmade expansion chamber on your pipe and feeling the difference it makes. I knew nothing about making them but I just dived in and did it. Anyone with one brain and two hands can make one.
I used my newly created Excel files to come up with these dimensions. Click here to read about how expansion chambers work and how extending the last cone (the baffle) extends the pipes powerband.
enjoy
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