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CB350/400 / Gearbox/Clutch Noise w/video
« on: April 14, 2017, 05:20:36 PM »
Good Day All -
I'm hoping one of you can help diagnose the cause of what I believe to be a clutch or transmission whine emanating from my newly rebuilt CB400F. It can be heard only when power is being transmitted to the rear wheel - i.e., there is no noise in neutral, or in gear with the clutch disengaged but if I place the front wheel against a wall and feed in the clutch a little, the whine becomes apparent. When getting underway and accelerating, it is quite pronounced but at steady roadspeed, it reduces somewhat. On trailing throttle, I can't hear it at all. Clutch operation is smooth, with no dragging or slipping, she snicks up and down through the gears nicely and neutral is easy to find. Search results from the two forums suggest it may be normal or it may indicate imminent catastrophic failure! Hopefully the video will help narrow it down.
https://youtu.be/2tdTc9uSn_U
Full disclosure, here: after reassembling the clutch, there was a part left over I wasn't too worried at the time, as I couldn't see anything resembling it in the parts manual exploded view and it wouldn't have been the first time a part from the CB450S my step-son was rebuilding in the same shed found its way into the my 400F's parts bins. I'm thinking now it might be relevant. Can anyone identify the part?
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Hopefully, the noise is coming from the clutch, as otherwise I'm afraid I'll have to split the cases again and I really don't know what I'd be looking for as all the bearings were replaced during the rebuild!
Thanks and Regards,
Brian
I'm hoping one of you can help diagnose the cause of what I believe to be a clutch or transmission whine emanating from my newly rebuilt CB400F. It can be heard only when power is being transmitted to the rear wheel - i.e., there is no noise in neutral, or in gear with the clutch disengaged but if I place the front wheel against a wall and feed in the clutch a little, the whine becomes apparent. When getting underway and accelerating, it is quite pronounced but at steady roadspeed, it reduces somewhat. On trailing throttle, I can't hear it at all. Clutch operation is smooth, with no dragging or slipping, she snicks up and down through the gears nicely and neutral is easy to find. Search results from the two forums suggest it may be normal or it may indicate imminent catastrophic failure! Hopefully the video will help narrow it down.
https://youtu.be/2tdTc9uSn_U
Full disclosure, here: after reassembling the clutch, there was a part left over I wasn't too worried at the time, as I couldn't see anything resembling it in the parts manual exploded view and it wouldn't have been the first time a part from the CB450S my step-son was rebuilding in the same shed found its way into the my 400F's parts bins. I'm thinking now it might be relevant. Can anyone identify the part?
[ Guests cannot view attachments ] [ Guests cannot view attachments ]
Hopefully, the noise is coming from the clutch, as otherwise I'm afraid I'll have to split the cases again and I really don't know what I'd be looking for as all the bearings were replaced during the rebuild!
Thanks and Regards,
Brian