Thread: Octane Question
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Old 05-02-2009, 12:41 PM
marioaz marioaz is offline
Motorized Bicycle Senior Member
Join Date: Dec 2008
Location: Prescott, Arizona
Posts: 65
Default Octane Question

Breaking in a new GT-4. NGK B6HS. Smaller plug gap, .020-.025 had the top end clanging and rattling. Predetonation? Re-gapped to .030 to retard the timing, and most of metallic rattling has ceased but bike a little slower on run up. Using Shell 87 octane. Does higher octane affect these engines as far as predetonation goes?
Grubee instructions plug gap is .036?
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