Primary Chains 101

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Misadjusted primary chains. Too tight a chain will cause a whine and might cause the clutch to drag. This condition lessens the life of all components parts, including bearings. A loose or stretched chain can be whipsawing on and off the front sprocket, which also would make lots of noise and a jerking sensation, especially in high gear. This may simply be a loose chain but more likely it would be an unevenly worn one with tight and loose spots and/or worn out hooked sprocket.
Do not confuse a whine in the drive train for primary chains before checking the rear belt tension. This can produce a sound similar to a low pitched siren and can damage your transmission bearings and inner primary also.