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Old 11-06-2013, 12:14 PM
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mapbike mapbike is offline
Motorized Bicycle Elite Member
Join Date: Mar 2010
Location: Central Texas
Posts: 5,379
Default Re: what did you do to your motorized bicycle today?

Made a mod to the X2 pocket bike expansion pipe on the Kulana, removed all the fiberglass packing, perforated baffle tube had fair high lip on the ID of the tube so I removed about 1/16" of the end of it to remove that restrictive lip, no pic of that part...., drilled extra holes in silencer cap to help release more exhaust that flows through perforated baffle tube, hoping this will get me back to my top speed that I had while running the shorty straight pipe while still maintaining the extra low to mid range power increase I've noticed since installing this expansion pipe, the extra low to mid pull is nice but I have lost around 6+mph on the top end and only have a 40MPH top speed on the flat since adding this pipe, low to mid pull is extremely increased with this pipe though, so much that I had to really tighten down my clutches main spring or when it came on the pipe it would just roast the clutch, I will be making up some Heavy Duty Clutch pucks for this one when I have time.

The pix don't show it but there is a long perforated tube on bottom side of cap that extends all the way down and mates up with the one seen down in the bottom of silencer chamber, it has a couple hundred 1/8' dia holes drilled through it, exhaust will fill chamber when engine is running and then pressure its way out from large center tube and hole I drilled around cap, this mod made it a bit louder but still much quieter than the shorty straight pipe was and it still has that nice ring ting ting expansion sound, noise level is still good and mellow, just a nice 2 stroke dirt bike sound.

Sorry pix aren't very clear, must have had some oil or gunk on my phones camera lens.

I dont always ride WOT, but when I do..I do my best to keep the rubber side down..Ride safely my friends!

Last edited by mapbike; 11-06-2013 at 12:21 PM.
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