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Old 10-17-2008, 07:35 AM
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jerseykat1 jerseykat1 is offline
Motorized Bicycle Elite Member
Join Date: Sep 2008
Location: North Plainfield, NJ
Posts: 134
Default Re: i think my "80cc" has issues. top speed only 28mph with shifter kit...

i think my motor is running good now, it is only limited by its ability to breath, i believe after i get a tuned pipe and port the intake and exhause i will be able to hit 35mph or more. I did however manage to hit 30 mph.

The problem is that the engine cant rev any higher because the port size is just not big enough (this is my theory), and i believe this is the problem because it runs better and revs higher without any air filter, so if the ports were bigger it would rev higher and thus allow a higher top speed.

I am not sure how far in i should go when porting the heads, should i port it all the way to the cylinder? will it run bad if i do that? could i port it without taking it apart and just use compressed air to blow out the debris or i guess i could just remove the cylinder head to get the debris out. anyone have any before and after pics of a ported China girl?
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