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Discussion Starter · #1 ·
is there much to be gained with polishing the exhaust and intake ports on my 580 ext? i am in the middle of a complete engine rebuild and while i have them off was wondering if it would be worth it to polish them up with the dremel. the sled has got a rumble pack can and SLP spring in the secondary if that makes a difference
 

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port and polishing can make a major change in the engine, because that is how thw engine breaths.by porting it you are releiving the restriction in the internals of the engine. however i would recomend that you dont do it your self because you can severily srew up your engine especailly if you dont now what you are doing. and both cylinders have to be matched exactly other wise the engine wont run well or at all. your best bet is to send them out and have a pro do them for you
 

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on that sled you have a bridge in the intake port, that needs to be sharpened like a knife on the side facing the carbs, on the bottom of the cyliner on each side you will see a small bridge, that needs to be sharpened like a knife, on that engine just doing that couple little things is worth a couple hp but a lot cripser throttle.
 

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Discussion Starter · #6 ·
okay thanks, i am planning on just polishing it, and like you said sharpen up those bridges.. i am just deciding on what to do, its going to be over 1000 bucks to rebuild by the time the crank gets done or i could get a used 900 or 700 twin for 1000... what would you guys do?
 

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I would not polish the intake ports. If you do your fuel will not atomize correctly. It probably wouldn't make a huge difference anyways but why lose any power? If you google it there is a lot of info out there on this. Sharpening the bridges prob isn't a bad idea though.
 
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