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I've always worked on the principle that new noises are the ones to worry about. Triples just seem to be noisier than fours. But spacecoast is probably right, if you only take up cable slack and the noise stops it's clearly not trans noise, it's in the actuating mechanism. Simple mechanical diagnosis.
 
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We're talking about just taking up a little slack, but not enough to lift the pressure plate.
Besides, there's enough friction remaining between friction and steel plates even with clutch fully disengaged to keep the transmission spinning in neutral. This is why motorcycles clunk into first gear and you feel them lurch forward a bit. (Same when on stand in gear with clutch disengaged the rear tire will still often spin)
 

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So I've read a lot of theories on why this happens on various clutches (seems to be a common noise among lots of platforms).

Best explanation that I shamelessly stole.:

"A piston engine crank doesn't rotate at a constant speed. The piston movements cause the crank to keep accelerating and decelerating during each rotation, just because of the inertia of the pistons and rods. Even with perfectly balance carbs or injection, the inertial torque pulses are still there, and when the clutch is engaged these pulses feed through primary reduction gears and clutch to the gearbox input shaft, adding mass to be accelerated and decelerated too. This adds some NVH - noise, vibration and harshness which almost all disappears when the clutch lever is pulled in."

This lines up with a guy on an R1 forum who said he fixed/massively reduced his chatter with the lever out in neutral that when away by pulling the lever in by adjusting his valves. On the surface that makes no sense, but if it smoothed out the engine, I could see it. I also read about people syncing their throttle bodies/carbs helping out too.
 

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This is a great thread about the topic. Mine does the exact same thing, opened up the clutch case cover days ago, ZERO wear on the push rod, or connecting teeth gears to clutch lever hinge, or on back side of the push rod next to the boss clutch bolt nut. I believe the out of sync firing post has it diagnosed correct, the clutch case cover is simple acting like a bell and resonating a sound in neutral extended lever position, ZERO clutch slippage, and no sign of metallics in oil. NATURE OF THE TRIPLE BEAST. RIDE ON
 
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