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Old 01-15-2010, 01:19 PM   #1
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I'm not sure that I understand what is done when a sled is "trail ported & polished" - can someone school me??
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Old 01-15-2010, 04:47 PM   #2
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Trail Porting is a mild port job that does not enlarge and reshape the ports as much as a Race Port job would. Polishing is referring to polishing the exhaust port walls with the hope of reducing turbulence in the name of increasing flow in the exhaust port. Do not ever polish the surfaces of the intake tract because you want, and need some texture to create turbulence to keep the fuel suspended in the air.
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Old 01-15-2010, 09:18 PM   #3
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A trail port is usually only a minimal change in size and or shape of the ports (ex. raise exhaust port roof 2mm) This keeps decent torque in the lower RPM ranges for trail riding w/o making the engine overly sensitive to jetting, temp etc. A race port can be drastic changes to port timing etc. (ex. raise exhaust port roof 4-5mm) This kills low RPM torque and horsepower, but creates a drastic improvement at very high RPM's, and makes the engine harder to start and idle and tempermental.
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Old 01-15-2010, 09:20 PM   #4
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A trail port is usually only a minimal change in size and or shape of the ports (ex. raise exhaust port roof 2mm) This keeps decent torque in the lower RPM ranges for trail riding w/o making the engine overly sensitive to jetting, temp etc. A race port can be drastic changes to port timing etc. (ex. raise exhaust port roof 4-5mm) This kills low RPM torque and horsepower, but creates a drastic improvement at very high RPM's, and makes the engine harder to start and idle and tempermental.
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Old 01-15-2010, 09:22 PM   #5
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Trail port = unnecessary expense for non-competition racers.
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Old 01-15-2010, 10:41 PM   #6
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<div class='quotetop'>QUOTE (94ZR580 @ Jan 15 2010, 04:47 PM) <{POST_SNAPBACK}></div>
 Quote:
Trail Porting is a mild port job that does not enlarge and reshape the ports as much as a Race Port job would. Polishing is referring to polishing the exhaust port walls with the hope of reducing turbulence in the name of increasing flow in the exhaust port. Do not ever polish the surfaces of the intake tract because you want, and need some texture to create turbulence to keep the fuel suspended in the air.[/b]

Well!! I beg to differ a little on this subject.. This goes all the way back to my motocross days in the early 80s, One of the best (HOP UPS). was Bench flow porting. IE. Blowing massive air thru the head (ports) and porting to the least resistance possible. It was amazing on our 2 strokes back then, ( I had mine done by (Mr, Know It All) From Dirt Bike Magazine= ($$$$). But it was well worth it. And was amazed how thin it was all shaved down, and how SMOOTH the INTAKE was. I have Opened, Ground and Polished the ports, INTAKE ports, and exhaust .On my 94 ZR 580. And 700. And they Screamed, and have never had another 580 or 700 beat them, Unfortunately the 580 had damage to where the tunnel meets the bulk head and I pulled the motor. I am still trying to find a chassis to put the motor in. Just bought a 95 and it still doesn't run right (wanted carb, its efi), But I got a good deal...
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