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Old 09-23-2011, 01:21 AM
atombomb232610 atombomb232610 is offline
Motorized Bicycle Member
Join Date: Sep 2011
Location: Milwaukee,Wi
Posts: 20
Default Re: Motorized Bicycle Take a Tip...Leave a Tip

In the start of this post it was suggested to replace your spark plug cap/boot. keep in mind if you use a cap as in the motorcycle type (usually ngk) they have a resistance rating somewhere around 1k. with a cdi this will change your timing. more resistance=less timing but a stronger spark. try using a standard automotive boot and connector as this is the way to lower your resistance and slightly advance the timing. high resistance will kill your ignition system (so will too low resistance but modern spark plugs have a good amount built into them.). most of your tuning will be done with an exhaust system. anyone that has a dirtbike can tell you the differance a expansion pipe and proper tuned exhaust can have. short exhaust (muffler close to the engine) equals a short power band that is torquey (good for people with shift kits or inclined driving conditions=hills and stuff). long exhaust will give you less initial torque but will smooth out high rpm running and will extend your powerband but lower overall torque and slightly increase overall horsepower. i have had the best luck with pocketbike expansion chambers (usually $30-$40 on ebay) and a sausage muffler ( small 2-4hp b&s muffler that ace hardware carries for $3.29) mounted at the end of the pipe. hers a pic of my build. genisis 29", 36t sprocket, port and polish, expansion pipe and removable muffler, custom tank, full motor teardown and rebuild before break in. including new gaskets and decking all pieces. i have hit 52mph on this bike. yes it was screaming like a banshee covered in acid and set on fire. that was within the first 100 miles and i have alittle over 400 miles on her now and it runs as good as new.
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