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Discussion Starter · #1 · (Edited)
Can someone confirm the correct torque spec for the rear axle nut on a CL72 or CL77? My Clymer manual says 142.32 ft/lbs, but this seems way too high. I have seen other references for CB's in the same year range being around 55-65 ft/lbs. I also have a couple of other service manuals for both CL & CB, but they say nothing about torque spec. Any help would be greatly appreciated. Thank you!

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I have a CB77 and agree that this is an absurd value. Perhaps there are two things that can guide you.
  1. The nut needs to be tight but must be manageable with the supplied wrench which is not very long.
  2. The nut needs to be tight enough to keep the axle in place even under full throttle in first gear. The adjusters are just that, adjusters, and cannot be used to keep the axle in place. They will just strip out or bend the screw.
I have never had a problem following my intuition with these nuts. Why not tighten it 'reasonably' and check it frequently until you have confidence in what you have done?
 

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Can someone confirm the correct torque spec for the rear axle nut on a CL72 or CL77? My Clymer manual says 142.32 ft/lbs, but this seems way too high. I have seen other references for CB's in the same year range being around 55-65 ft/lbs. I also have a couple of other service manuals for both CL & CB, but they say nothing about torque spec. Any help would be greatly appreciated. Thank you!

 

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Discussion Starter · #4 ·
I have a CB77 and agree that this is an absurd value. Perhaps there are two things that can guide you.
  1. The nut needs to be tight but must be manageable with the supplied wrench which is not very long.
  2. The nut needs to be tight enough to keep the axle in place even under full throttle in first gear. The adjusters are just that, adjusters, and cannot be used to keep the axle in place. They will just strip out or bent the screw.
I have never had a problem following my intuition with these nuts. Why not tighten it 'reasonably' and check it frequently until you have confidence in what you have done?
These are all really good points, thank you. I had used my wrench to tighten it to ~55 ft/lbs, but will redo it by hand. I wrecked the rear wheel bearings on my first bike after forgetting the inner-wheel spacer, so am a little paranoid about correct tightness.
 

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74 CL360, 81 CM200T, 85, 86 & 87 CMX250. Invisible to cages, treat accordingly. Avoids Road Rage!
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Can someone confirm the correct torque spec for the rear axle nut on a CL72 or CL77? My Clymer manual says 142.32 ft/lbs, but this seems way too high. I have seen other references for CB's in the same year range being around 55-65 ft/lbs. I also have a couple of other service manuals for both CL & CB, but they say nothing about torque spec. Any help would be greatly appreciated. Thank you!

Good call asking before following the destructions in the Clymer regarding torque! These have been known to be very incorrect as you've discovered yourself. Very wise to ask!
If you can find a Honda CL 72/77 Manual, you won't go wrong.
 

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Discussion Starter · #9 ·
Good call asking before following the destructions in the Clymer regarding torque! These have been known to be very incorrect as you've discovered yourself. Very wise to ask!
If you can find a Honda CL 72/77 Manual, you won't go wrong.
Hey, thanks! Yeah, it seemed super suspicious. And thanks for the tip on the Honda manual. Will keep an eye out for one on ebay. This forum has been really helpful pinning down the correct values. Cheers.
 

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These are all really good points, thank you. I had used my wrench to tighten it to ~55 ft/lbs, but will redo it by hand. I wrecked the rear wheel bearings on my first bike after forgetting the inner-wheel spacer, so am a little paranoid about correct tightness.
If you have the original nut, being able to get the cotter pin inserted is an excellent guide along with the above advice using the original wrench and little cheater that comes in the tool kit.
 

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Discussion Starter · #13 ·
Your first clue that something is wrong is the 142.32 ft/lbs. Nothing will ever give the torque in ft/lbs as a decimal number.​
No joke. I'm curious as to what normal person has a torque wrench that is accurate to the hundredths of a ft/lb. My ancient beam-style Craftsman can't possibly be more accurate to ±2 ft/lbs or so.
 

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No joke. I'm curious as to what normal person has a torque wrench that is accurate to the hundredths of a ft/lb. My ancient beam-style Craftsman can't possibly be more accurate to ±2 ft/lbs or so.
I doubt anyone could afford such a device.

The value may be a metric to colloquial units calculation error. My amazing ability to miscalculate is the reason I don't use anything but metric on machines designed to metric standards, if I can. My edition of the CB77 service manual contains a few such errors - no doubt others do as well - so the conversions should always be checked.

As for the extreme precision, people often show more digits than are justified by the initial value. In this case, as xcopy mentions, digits after the decimal point are extraneous. In general, if the value you wish to convert has, say, three digits of precision, the converted value should no more than three. This is referred to as Significant Figures.

The Mars Climate Orbiter disaster is a great example of why it is not a good idea to work in two systems of units at the same time. Even the pros can get it wrong.
 
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