'73 R60/5 - Isolated Clattering Sound

Hi Gang

Finally put my bike up on the lift tonight - I inspected driveshaft flange and U Joint - new bolts are tight and so is U Joint

With bike in first gear, when I pull in clutch to disengage and rotate the rear wheel, I'm getting the clack clack sound I described in earlier posts - If I were to guess, there's probably about 1/4" - 1/2" free play in the rear wheel between clacks. When I release the clutch, in first gear the clack stops but the free play is the same.

Could this be the sound of the diaphragm spring or possibly the interaction between the tranny output shaft and the clutch?

Look in the timing hole and watch the flywheel when you pull the clutch lever. Make sure the flywheel doesn't move when you do that. Just a thought.

I get a bit of a clack clack sound when I push my /6, clutch disengaged and in first gear. Quiets right up when I tip the lever into neutral. I think it's the normal freeplay in the trans when a gear is engaged.

If it helps, I get less clack clack when I pull the lever all the way to the grip--so it might be a wee spot of clutch drag in your case.

melville said:

I get a bit of a clack clack sound when I push my /6, clutch disengaged and in first gear. Quiets right up when I tip the lever into neutral. I think it's the normal freeplay in the trans when a gear is engaged.

If it helps, I get less clack clack when I pull the lever all the way to the grip--so it might be a wee spot of clutch drag in your case.

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I know the flywheel is tight - it's not a persistent problem but the sound is coming in clutch/tranny area. Thanks for the replies!

Ken, I have a /5 on my lift right now. I will try to replicate your procedure and report back what I find.

kentuvman said:

I know the flywheel is tight

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Ken -

I was thinking more about fore-aft movement of the crank. What I'm wondering about is if the bolts on the back side of the clutch pack are whacking the forward side of the transmission housing. I guess it would affect the clutch action in all gears, not just taking off in first.

Ken, I just did a trial with the bike on my lift.

With the bike in first gear with the clutch pulled in here is what happens. If I turn the wheel backwards, in less than a quarter turn I hear 1 clack. If I then turn the wheel forward, in the same distance I hear 2 distinct clacks. These are coming from the transmission. I would attribute this the slack between the gearsets taking up in the transmission. I can also hear the shushing sound of the friction disc turning inside the clutch assembly.

Please note that I do not hear the double clack unless I turn the transmission backward first. Also, I do not detect this phenomenon from the drivers seat with the motor running. I suspect that this is because that even with the clutch lever pulled, the spinning of the flywheel would pre-load the transmission gearsets right up to the point where the inertia of the sitting vehicle would over come the torque transmitted through the clutch when the lever is pulled in.

I would advise you to put 500 to 1000 miles on the bike, then drain the transmission oil into a clean container and then strain it thru a fine mesh to look for shiny flecks. I suspect there is a bearing in the transmission starting to fail. In fact, I once found a fleck the size of a fingernail clipping on the magnetic drain plug from a /5 transmission that was going bad. You would be looking for anything bigger than the micro-futz normally attracted to the magnet.

James.A said:

I would advise you to put 500 to 1000 miles on the bike, then drain the transmission oil into a clean container and then strain it thru a fine mesh to look for shiny flecks. I suspect there is a bearing in the transmission starting to fail. In fact, I once found a fleck the size of a fingernail clipping on the magnetic drain plug from a /5 transmission that was going bad. You would be looking for anything bigger than the micro-futz normally attracted to the magnet.

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Thank You, James - sounds like a very reasonable diagnosis, as sound is coming between clutch & tranny. Will follow your suggestion and report back when I get to that point.