Rear Axle Torque for the '75

YamadudeXS650C

YamadudeXS650C

Central New York XS650
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I just finished replacing the chain, sprockets and rear tire on the '75. All is good, and the R & R of the exhaust system to accommodate these repairs was no big deal.

However, I am loath to R &R the exhaust or shocks to do a simple chain adjustment in the future, and I want to plan ahead for this.

I have a 12" adjustable spanner which will easily loosen the nut, but the torque on the tightening is the issue. I have a 50 lbs fish scale, and I could easily bolt a bar metal extension/cheater on the wrench. A slip-on pipe section would not fit in the cramped space:

004.5.jpg

005.JPG


Could someone give me the value for "A" and "B" to achieve the 108 ft-lbs indicated by the Yamaha Service Manual?

I just drew this up on Cad-Cam ( :) )
006.JPG



Thanks !
 
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Since the force of the angle is 90 to the wrench it's Torque=Force(distance)sin(90). Sin(90)=1. Final torque is 108ft/lbs the other information you need is your force and your distance. The farther away from the bolt the force is the less force is needed to create the 108ft/lbs needed. If you're wanting to make out your scale at 50lb of force roughly 2'2"
 
hippiedreads said:
Since the force of the angle is 90 to the wrench it's Torque=Force(distance)sin(90). Sin(90)=1. Final torque is 108ft/lbs the other information you need is your force and your distance. The farther away from the bolt the force is the less force is needed to create the 108ft/lbs needed. If you're wanting to make out your scale at 50lb of force roughly 2'2"
Click to expand...
Dude !!!!
Thank you.
I'd like to say that T=FD is in my head somewhere, waiting to be retrieved, but it is not.
Too much ganja and hi-volume Led Zeppelin since my college Physics classes.
Much appreciated.
So, "A" = approx. 2'2" if "B" is 50 Lbs.
 
A=get a decent open end and put the crescent away.
B= tighten it as tight as you can keeping the castle nut slots inline with the holes in the axle while you are C holding the rear brake to center the hub.
 
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What you're doing is absurd. Either follow WER above, and tight as you can means as tight as you possibly can, or else disconnect the shocks from one end and let the wheel fall so you can get a 27mm socket and torque wrench on the nut.
 
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I agree with both the other guys though, a bit of over kill, tighten the hell out of it by hand and line up the hole for the cotter pin. Also if there is a harbor freight near you the regularly run deals on their torque wrenches that make them pretty cheap (i.e. $15 or so) they also sell cheap sockets which will work fine for your larger sizes you don't often use. It would be a good idea to get the three standard sizes of 1/4" 3/8" and 1/2" but if you're keeping a budget the 3/8ths will do most of the torques you'll need for working on bikes.
 
hippiedreads said:
I agree with both the other guys though, a bit of over kill, tighten the hell out of it by hand and line up the hole for the cotter pin. Also if there is a harbor freight near you the regularly run deals on their torque wrenches that make them pretty cheap (i.e. $15 or so) they also sell cheap sockets which will work fine for your larger sizes you don't often use. It would be a good idea to get the three standard sizes of 1/4" 3/8" and 1/2" but if you're keeping a budget the 3/8ths will do most of the torques you'll need for working on bikes.
Click to expand...
Thanks, dude, I've got all the wrench stuff. You see, on a '75, you can't get a socket on the nut without removing the exhaust or shocks. See picture. But you've been helpful.
 
xjwmx said:
What you're doing is absurd. Either follow WER above, and tight as you can means as tight as you possibly can, or else disconnect the shocks from one end and let the wheel fall so you can get a 27mm socket and torque wrench on the nut.
Click to expand...
Those who have gotten to know me have come to realize that I traffic in absurdities.
After all, I'm the guy who posted this picture within a discussion of motorcycle safety:

3690209a553e1b0fc27babec35fe0334.jpg
 
Not on your specific muffler but you could loosen the muffler clamp and any hardware securing it to the fram and that will give you the ability to pull it away from the bike some. That or spray some WD where the muffler connects to the head and slide it off. It's really quite quick if they aren't mated too tightly.

Another option, buy a 27mm crows foot which can also be found at harborfreight for cheap. Makes your torque a little less accurate but if your at 100ft/lbs with a cotterkey you'll be fine.

You've probably got more than enough information now... side note I'm stealing that picture lol. Good luck man.
 
hippiedreads said:
Not on your specific muffler but you could loosen the muffler clamp and any hardware securing it to the fram and that will give you the ability to pull it away from the bike some. That or spray some WD where the muffler connects to the head and slide it off. It's really quite quick if they aren't mated too tightly.

Another option, buy a 27mm crows foot which can also be found at harborfreight for cheap. Makes your torque a little less accurate but if your at 100ft/lbs with a cotterkey you'll be fine.

You've probably got more than enough information now... side note I'm stealing that picture lol. Good luck man.
Click to expand...
Now, yer talkin', dude.
Obviously, I don't have ALL the wrenches out there, but many, and I was thinking along the lines of a crowsfoot, but couldn't put my finger on it. I have a "special tool" for the steering head torque on my FJR, a sort of crowsfoot C-Spanner,
images


and I was thinkin' of something similar, and you named it.
Unfortunately, HF only sells sets. However, I see online that I can get an individual crowfoot wrench various places. And the conversion is pretty simple:

The formula for calculating the torque with a crowsfoot. E- Effective length of extension - measured along the centerline of the torque wrench. L Lever length of the wrench - center of grip to center of drive. T(W) - Torque set on the wrench. T(E)- Torque applied by the extension to the fastener.

T(W) = T(E)* L/L+E
T(E) = T(W)* (L+E)/L

However, I believe that the CF will bring the torque "close enuf" to not have to do the math. Math and I are not good friends.

You may steal all my pics. :)
 
I don't torque Jap axles with cotter keys, never have and never will. I just make them really tight, then a bit more or less to align the cotter pin hole. So let me ask you this? What are you going to do when you finally achieve that "magic" 108 pounds and the cotter pin holes don't line up? It seems you're in for many sleepless nights knowing your axle is at 104 or 110 instead, lol. A single value torque spec for a fastener that gets cotter pinned is just plain stupid.

In perusing the various 650 factory shop manuals, I have found a better torque chart, the one in the '77D manual. It gives all the torque values in ranges .....

UwdyxX1.jpg


For the rear axle, that would be about 87 to 130 ft/lbs. If I was to use a torque wrench, I would tighten it to 87 then as much more as needed to align the cotter pin.
 
5twins said:
I don't torque Jap axles with cotter keys, never have and never will. I just make them really tight, then a bit more or less to align the cotter pin hole. So let me ask you this? What are you going to do when you finally achieve that "magic" 108 pounds and the cotter pin holes don't line up? It seems you're in for many sleepless nights knowing your axle is at 104 or 110 instead, lol. A single value torque spec for a fastener that gets cotter pinned is just plain stupid.

In perusing the various 650 factory shop manuals, I have found a better torque chart, the one in the '77D manual. It gives all the torque values in ranges .....

UwdyxX1.jpg


For the rear axle, that would be about 87 to 130 ft/lbs. If I was to use a torque wrench, I would tighten it to 87 then as much more as needed to align the cotter pin.
Click to expand...
Must be a really slow day on the 'ol website for this topic to get this much attention :laugh2:

Imagine if I had decided to report the actual torque figure in the Yamaha Service Manual: 108.5 (no joke)
 
You should be good with that because before I discovered the '77D chart, I ran across this one from the '76 XS500C model. It uses the same axle diameters and wheel bearings so I don't see why these values couldn't be applied .....

tAPwOpB.jpg
 

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