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I went for a ride today and removed the left side cover so I could see what the vacuum advance was doing. It operates smoothly with a little bounce at certain rpms...not a concern. It goes to full advance at highway cruising speeds. The bike runs very well, but at hiway cruising speeds, there is a feint rapping noise which seems to come from the front of the engine...mostly when accelerating. I thought maybe I had an exhaust gasket leak, but to experiment, I carefully reached down and pulled the vacuum advance back with a gloved finger. The rapping noise disappeared. I stopped, disconnected and plugged the vac advance hose and rode on. The bike seemed to pull stronger throughout the rev range. Even the exhaust note seems to pulse stronger. Maybe it's my imagination. Would these symptoms indicate that perhaps the noise is detonation and the timing plate is too far advanced? As far as I know, timing hasn't been adjusted since manufacture. I don't have a timing light but I'm thinking it might be a good investment. Comments?
ps: I'm running stock jets, BP7ES plugs and a UNI air filter if that matters in the analysis.
ps: I'm running stock jets, BP7ES plugs and a UNI air filter if that matters in the analysis.
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