Topic: CB750 top triple tree troque

[Vin750]

Hi all, I am sure this has been asked many times. I searched through old posts but it’s still unclear. And I don’t think the shop manual mentions it either.

We all have seen so many broken unicorn triple trees. Sometimes even with the D washers.

I am referring to the pinch bolts that hold the fork tubes.

So what’s the correct torque value to be safe?

Some old timers I know say they just do it by hand but I don’t do this every day and I would rather be safe than see it come loose or break.


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[MauiK3]

Others may know better but as I recall it's an 8 mm bolt and I think it's likely to be about an 8.8 strength which would call for about 16 ft. lbs. dry or 20 ft. lbs. lubricated.
The heads of the stock bolts are chromed and don't have a grade marking but I don't think Honda would use a low grade bolt in this location.
If it's even stronger (10.9) the torque goes to 20 dry and 30 lubricated. I'm not sure I'd assume it's 10.9 without positive proof.

[Vin750]

Others may know better but as I recall it's an 8 mm bolt and I think it's likely to be about an 8.8 strength which would call for about 16 ft. lbs. dry or 20 ft. lbs. lubricated.
The heads of the stock bolts are chromed and don't have a grade marking but I don't think Honda would use a low grade bolt in this location.
If it's even stronger (10.9) the torque goes to 20 dry and 30 lubricated. I'm not sure I'd assume it's 10.9 without positive proof.

It can’t be that much, if you put that much torque on the pinch bolt of the triple tree you will probably destroy it.


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[MauiK3]

Perhaps, I don’t recall seeing a spec anywhere

[HondaMan]

I would stay around 100 in-lbs (8 ft-lbs) if you are looking for a number. The 1969-1975 version of the top tree is different from the later ones. The late K5 and the K6 top tree uses 7mm pinch bolts instead of 8mm, and can withstand the same torque as above. This version does not have the D washers, though.

[Vin750]

I would stay around 100 in-lbs (8 ft-lbs) if you are looking for a number. The 1969-1975 version of the top tree is different from the later ones. The late K5 and the K6 top tree uses 7mm pinch bolts instead of 8mm, and can withstand the same torque as above. This version does not have the D washers, though.

Thanks Hondaman for the info. I want to make sure I don’t over or under so it.


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[BenelliSEI]

Just use a 1/4 drive short ratchet, and pull it “tight”. Torquing small screws can lead to a lot of surprises. If you must use a spec, get a good quality, 1/4 drive inch/lbs. torque wrench. My best Snap-on 3/8” torque wrench get’s inconsistent under 10 ft/lbs.

[Don R]

 What he said ^.

[Old Moe Toe]

As it happens I tightened up my top triple tree mounts today. They are new second hand ones as my old ones got broken, and had been welded back up...and seemed to be ok for lots of miles. But I wanted unbroken ones. So anyway tightened the new ones up as far as I dared by feel and the D shaped washers were still rattling around in there.
Is there a certain thickness those wascally D shaped washers are meant to be?.

[david 750f]

Around 0.090. Or (2.28mm)

http://forums.sohc4.net/index.php/topic,72765.0.html

[ekpent]

As it happens I tightened up my top triple tree mounts today. They are new second hand ones as my old ones got broken, and had been welded back up...and seemed to be ok for lots of miles. But I wanted unbroken ones. So anyway tightened the new ones up as far as I dared by feel and the D shaped washers were still rattling around in there.
Is there a certain thickness those wascally D shaped washers are meant to be?.

Member Johnie would know the answer to that as he had a large batch of them made to the proper specs and sells them in the classified section. http://forums.sohc4.net/index.php/topic,179424.0.html

[Old Moe Toe]

Around 0.090. Or (2.28mm)

http://forums.sohc4.net/index.php/topic,72765.0.html

Excellent reply David 750F, Thanks.