From expressly mopeds. Port timing is critical on 2-strokes:
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the port timing of different honda engines
the NU50 express engine has these values exhaust port opens 67.5 degrees from top of stoke
scavenge opens 47.5 degrees from top of stroke
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on the Spree engine the exhaust port opens 71 degrees from top
and the scavenging port opens 52 degrees from top
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on the ELITE engine the exhaust port opens 80 degrees from top
and the scavenging port opens 56 degrees from top
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the NA/NC engine exhausts port opens 65 degrees from top
and the scavenging port opens 47 degrees from top
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the SR express /NX50 exhausts opens 67 degrees
scavenging port at 47 degrees
--- Jul 28, 2009 ---
Updated by: mousewheels
Reason: Add additional info
Terminology: BBDC = 'Before Bottom Dead Center', ABDC = 'After Bottom Dead Center'
All values are in degrees
Port timing for various Honda 50 scooters
Moderator: FAQ Moderator
Port timing for various Honda 50 scooters
Admin, Hondaspree.net
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