my quest for 50mph with DIY and bolt-on mods.

Jayraye39

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Jul 13, 2021
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Ok after a 3week span of no starts. I replaced my crank seals and the bike runs nice and agressive. So im back to my original ission which is to hit 50mph with diy mods only.

Im running a triple 40 69cc with 26 x 2.3 wheels. My mod list and top speeds are as follows

homemade expansion chamber, case match, port matched, enlarged exhaust port, enlarged intake port. Transfer ramps on piston crown, timing retard, catnip cdi modified with a polaris stand alone coil. custom 4in by 17mm intake tube, bored out bofeng carb, decked cylinder, decked cnc head 7cc. with thoes mods i was able to hit 43mph. tops.

I eliminated the head because of a stripped spark plug hole. The stock head increased my compression because of it being 5.5 or 6cc.
( dont know what my compression reads) but its more with the stock head. the head was modified for a better squish band ring and matched the dia of chamber to the dia. of the piston. my top speed increased 46mph.

Recently had to change cases for a stripped jug thread. in doing so I stuffed the case using jb weld. this increased my case compression which helps leveling out the force of the cylinder compression. Ran it just now for a top speed run and I hit 48mph.
 
I'm thinking shaving a couple unnecessary pounds off your bike might help you out a tad. Could you post a picture so we might be able to see what weight you could drop without harming the aesthetics.
 
well im thinking of just getting the 17mm bing carb. with my port work it can definitely handle more charge. ive read many have had increased performance with a larger carb. just trying to get one under $40 is hard. unless i wait 2months for china to send one
 
well im thinking of just getting the 17mm bing carb. with my port work it can definitely handle more charge. ive read many have had increased performance with a larger carb. just trying to get one under $40 is hard. unless i wait 2months for china to send one
Maybe you could do a bit of research on boost bottles and see what you can come up with.
 
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