Tightening Torque ???

[nic_oz]

Hi

I changed the rear sprocket today and the service manual says to tighten the bolts to 69NM, sounds like a lot but that's what they say hey.

Well I stripped the thread from the bolt !!

Yes, I did do it in criss cross pattern and increased the torque gardualy exactly as they say.

Is there a typo in the service manual ?
I looked at some other torques and they have some outrageous values for tiny bolts, on M9 is 110NM !!!!

Nic

[alan]

Um doing mine next week changing sprocket etc ill have to look at the torque settings in my Haynes manual see what it says could be a miss print .Haynes says 60 nm which is about 45 ft lb aprox.ill let you know how i get on

[dapleb]

Rear sprock is 60Nm on the 850's, not had a problem with that. So 69Nm for the 900 sounds about right.

I have noticed however that the bolts/screws on my 15y.old mkI are in general much better quality than on my 9y.old mkII...perhaps the 900 is just inline with the use of ever cheaper parts and fasteners!

Some of the torque settings are just not attainable (or neccessary), like the 64Nm on the lower reat shock mounting bolt, have tried on both mine and Wicky's bikes with brand new Yam bolts and couldn't get near that before the BOLT thread stripped!

I always double check any suspect torques with the workshop manual...BEWARE there are torque spec errors in both Haynes and Workshop.

Cheers
dapleb

[steveglover]

It does sound like a lot for a M10 nut, but the Bandit has a similar spec (60Nm) so the 69Nm is probably right.

It is possible to be too careful with a torque wrench, and overtighten the nut. If you try to approach the final torque setting a bit at a time you are likely to overtighten. On a rear sprocket I'd do the criss-cross business to about half the torque setting, then tighten each nut to the final torque setting in one go. Never had any problems that way.

[nic_oz]

In the end I set them to 40NM, the stripped bolt still had a bit of thread left so I tightend that the best I could but need to replace asap.

aytcat, just watch out the front spocket nut is 36mm, not very common and you will probably need a impact wrench to get it off, mine did anyway.

I agree some torques make no sense at all in the service manual, comon sense should previal.

Nic

[Guest]

Yeah I stripped some bolts (just around fairings etc) just by following the "proper" procedures - like above..bit o' common sense next iem (I shouod have known better really!

[alan]

<!--quoteo(post=820:date=Sat 25th Mar 2006, 11:56 AM:name=nic_oz)-->QUOTE(nic_oz @ Sat 25th Mar 2006, 11:56 AM) <{POST_SNAPBACK}><!--quotec-->In the end I set them to 40NM, the stripped bolt still had a bit of thread left so I tightend that the best I could but need to replace asap.

aytcat, just watch out the front spocket nut is 36mm, not very common and you will probably need a impact wrench to get it off, mine did anyway.

I agree some torques make no sense at all in the service manual, comon sense should previal.

Nic<!--QuoteEnd--><!--QuoteEEnd-->


Yea Got that size Socket cause its the same size as a VW aircooled flywheel nut and i had to rebuild that engine.That needed a scaffolding bar aswell to undo the thing and to tighten it up to the torque spec,cant remember the settings something silly like 175ft ftlbs