Jump to content
Sign in to follow this  
eraser8

rear sprocket nut torque

Recommended Posts

eraser8
Hello guys,
another technical question. Like I said in another post, I checnge my rear sprocket. When I put back the new sprocket, I tried to tighten the nuts to the specification torque 57 lbs/ft with cross pattern. The problem is... I was not be able to tighten them t0 57 lbs. currently, they have about 40 - 45 lbs/ft. The reason is, each time I give it a quarter turn with the torque wrench, at the begginning, the tension was progressive. Each time it was more and more hard. But on a certain point, (about 40-45 lbs) it is not giving more torque. 
 
After seeing that, I immediatly stop torquing the nuts... BTW all nutss have done this weird thing. My fear was that the bolt was being stretch or the bolt was going to strip the hub... 
 
So, for now, everything seems really tight, but the nuts are not torqued to the specification.
 
Have you already experiment the same thing?
 
THanks
 
 

Share this post


Link to post
Share on other sites
bmwpowere36m3
Is your torque wrench calibrated? If the torque doesn't seem to be increasing, then likely threads and bolt are starting to deform/stretch. If you have a "feel" for hand-tightening hardware, it's a similar feel.
  • Like 1

Share this post


Link to post
Share on other sites
eraser8
Yes my torque wrench is well calibrated. Do you guys change the studs when you change the sprocket? If these stud are suppose to handle 58 lbs/ft, how these can stretch at about 45 lbs? Is it 1 time use stud?

Share this post


Link to post
Share on other sites
bmwpowere36m3
What size fastener is it? M8, M10... 58 ft-lbs seems high. I only torque the axle nut to 60-65 ft-lbs. Unless you have your torque wrench checked periodically, then the cal is at best a guess.

Share this post


Link to post
Share on other sites
eraser8
Hi bmw,
 
It is clearly write M10 for "rear wheel sprocket nut" with a torque of 80 nm (58 lbs/ft)
Yes I did a test recently on my torque wrench, plus, I have an electronic torque wrench kit which I used to do the tightening.
 
Do you think I would be better to replace all stud and nuts?
 

Share this post


Link to post
Share on other sites
bmwpowere36m3
Service manuals are wrong sometimes.... either the spec is wrong, your wrench is inaccurate, or the hardware is damaged.
 
Hard to tell which.

Share this post


Link to post
Share on other sites
Guest Ralph
If they are studs and threaded into the hub I would have a look
at those threads see if the stud was being pulled out of the hub.

Share this post


Link to post
Share on other sites
eraser8
Hi Ralph,
 
 
I checked that when I torque them and the studs didn't turned into the hub. This is why My feeling is the stud have been stretched a little.
 
 

Share this post


Link to post
Share on other sites
eraser8
How you guys torque the sprocket nut? how many lbs/ft?

Share this post


Link to post
Share on other sites
bmwpowere36m3
Not everything needs to be tightened with a torque wrench… I think it's a common mistake among many people who wrench. They get a false sense of security and blindly follow "torque" specs, which at times are incorrect in service manuals. Those sprocket studs and nuts are shared with other Yamaha models and stripped nuts/studs is not unheard of. Yamaha R1 spec calls for 72 ft-lbs! The front sprocket doesn't even call for that kind of torque and the fastener is MUCH larger.
 
Here two threads: http://www.r1-forum.com/forums/4-mechanical-help/249104-hmm-stripped-threads-rear-sprocket-bolts.html & http://www.r1-forum.com/forums/2-general-motorcycle-discussions/234725-sprocket-torque-specs.html
 
Red loctite the studs (make sure their not stripped) and torque the nuts to 28-40 ft-lbs. Tighten in stages and criss-cross pattern. The issue might not be the hardware itself (stud and nut), but that they thread into cush-drive… which I would't be surprised if it was aluminum.

Share this post


Link to post
Share on other sites
pattonme
good god, 25ft/lb is PLENTY for sprocket nuts (rear). If not using ridged flange nuts, a dab of 'blue' will do ya.

bannerfans_1095431.jpg

Share this post


Link to post
Share on other sites
Guest Ralph
If you do a lot of nut tightening you just get a feel for it, you can feel the bolts start to
stretch, I used to rebuild a lot of industrial engines and one day wile doing a Briggs Stratton
in walk two company reps, they could not believe I was not using a torque wrench I told them
I had done hundreds and never had a fail but no they were amendment so I told them to go get
their wrench and test my tightening, it was spot on, the gave me the torque wrench a lovely little
bit of no doubt expensive kit and buggered off, still regret leaving it when I retired.
 

Share this post


Link to post
Share on other sites
eraser8
Thnaks guys for all informations.
 
So, In breif, we cannot follow the instruction in the yamaha service manual? It's a little scam..... They say to torque them to 58 lbs and after we broke everything, they make a pleasure to sell us new parts!!!
 
Dawn... I own 2 yamaha R1 in the past and got good experience with them... But since I got my FZ07, it's the third time I have to deal with some strange situation like that...
 
So now, do you think I should change all studs ? Of what I understood, they could be streched a little since I torque them "too much for this kind of stud".
 
Thanks

Share this post


Link to post
Share on other sites
pattonme
the FZ09 manual states chain slack should be 10mm or something asinine like that. So whomever Yam has doing sanity checks and copy editing is asleep at the wheel. Also had a case where the cam sprocket bolts backed themselves out - Yam doesn't believe in loctite and instead had the torque value WAY up. Me personally cam sprocket bolts ALWAYS get a dab and the torque should be as low as possible to prevent warping the cam.
 
But in any event your sprocket bolts are probably fine. The rear axle nut seems to be problematic on some bikes - destroying the axle in the process. I don't have the dimensions handy but Pro-Bolt USA might have a suitable replacement if McMaster doesn't.
 
 
https://www.probolt-usa.com/stainless/stainless-steel-motorcycle-special-parts/stainless-steel-axle-nuts-bolts.html

bannerfans_1095431.jpg

Share this post


Link to post
Share on other sites
eraser8
Thanks Patton for all infos
 
So, I think I will unscrew all sprocket nuts, inspect the studs if they are good and reinstall the nuts with red loctite. Also, I will go with 25-30 lbs of torque.
 
Does this seems a good way to go?

Share this post


Link to post
Share on other sites
eraser8
About the Axel bolt, the dealer will give me the original one. I would prefer to go with a standard one (non self-locking nut) to avoid any future problem like I just have. But if I go with a standrad one, I will need to drill the axel to be able to use a cutter pin? I need a way to avoid the Nut unscrewed by itself!
 
I also say a SelfLocking nut with teflon... Does the teflon is enough hard to avoid the nut unscrewed by itself?

Share this post


Link to post
Share on other sites
bmwpowere36m3
Red (hi-strength) loctite the studs into the cush drive... and blue (medium-strength) Loctite on the nuts. Or just leave the studs alone and a dab of blue Loctite and reinstall the nuts.
 
For the axle nut you can either put in a castle nut and cross-drill the axle... though the adjuster plate recess might make fitting a cotter pin or r-clip difficult. Or just use a nyloc.

Share this post


Link to post
Share on other sites
eraser8
Does a Nyloc will do the trick as well as metal lock (OEM)? And also which torque would you use?

Share this post


Link to post
Share on other sites
Guest Ralph
Just looked at the FZ-09 same wheels and they give the same torque, the spec for the R6 -600 is much higher.
so maybe the figure is right and something else is going on.

Share this post


Link to post
Share on other sites
pattonme
the OE metal 'finger' lock seems to cause problems. Nylock will do but heck a standard nut will be fine too. I have yet to have an axle nut do anything but stay put. A real light daub of anti-seize can be used but then you need to pin the nut and use a lower tightening torque. Best would be to chase the threads on both the axle and nut before installation and go to ~50-60ft/lb. Then dribble in some green.

bannerfans_1095431.jpg

Share this post


Link to post
Share on other sites
eraser8
Hi Patton,
 
Thank you for the tips! I do understand all the xplanation but what it the "dribble in some green"?
 
Also, if I decide to go with some anti-seize, how much torque you would use? I saw when we use lubrication, we must use about 75% of the recommended torque. So, here the 76 lbs would become 57... What do you think?
 
 

Share this post


Link to post
Share on other sites
pattonme
'green' = green locktite. You put it on AFTER things are tight. I would use the 75% figure calculated from 60ft/lb with antiseize. 75ft/lb dry is just insane IMO. Best is clean the threads (wire brush) leave the seize off, and tighten to 50-55. Add some Green and call it done. Periodically check but I've never had one come loose even without the locktite.

bannerfans_1095431.jpg

Share this post


Link to post
Share on other sites
eraser8
Thanks a lot Pat! maybe the 76 lbs torque could be the reason why the nut has been stuck after 5-6 time use? First, I will ask the dealer when he will receive all my parts, how much torque they put on the wheel nut and also on the sprocket nuts. From that, I will see what I will put but 60 lbs seems a good option and if I put anti-seize, 45 lbs will do it.
 
Thanks again for all infos.
 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  


×

Important Information

By using this site, you agree to our Terms of Use.