Torque talk..... and other workshop manual incorrect info!

[AndyW]

Having found the old discussions regarding sprocket retaining studs stripping and what the correct chain tension should be and the related comments re incorrect info in the workshop manual I wondered what other tech date and instructions have been found to be wrong??

Would be good to collect such details in one place

[jthayer09]

Chain tension is the only time a spec has been "wrong" - too tight - in the shop manual for FJ09/Tracers that I can remember off the top of my head; this has been corrected in the Gen3 (2021+) shop manuals.

Screw/nut/bolt stripping is due to Yamaha writing torque specs assuming new parts (fresh threads). If you're reusing fasteners, then you need to apply less torque as threads wear over time due to vibration and screwing/unscrewing as you service the bike.

In contrast, Harley service/repair manuals usually give a torque range on their fasteners, you can use the lower range on old bolts.

Either buy new bolt/nuts or do 10% less torque, especially for fasteners in high vibration or torque environments.

[AndyW]

That's a really good point re wear that had not occurred to me, thanks 👍  And as all the bolts I've been working with on the Tracer so far are dry i.e. no locktite or grease lubricating the thread on install (and preventing corrosion and/or galling) that will be more relevant.

Re the sprocket nuts I have it on good authority that the recommended setting of 80Nm (59lb ft) is way too high (as others have said here on the forum). I was advised 40 to 50Nm MAX which sits right with the generic/typical figures for M8 bolts found on the net...

(source: https://www.engineeringtoolbox.com/)

Edited Monday at 11:29 AM by AndyW

[skipperT]

3 hours ago, AndyW said:

That's a really good point re wear that had not occurred to me, thanks 👍  And as all the bolts I've been working with on the Tracer so far are dry i.e. no locktite or grease lubricating the thread on install (and preventing corrosion and/or galling) that will be more relevant.

Re the sprocket nuts I have it on good authority that the recommended setting of 80Nm (59lb ft) is way too high (as others have said here on the forum). I was advised 40 to 50Nm MAX which sits right with the generic/typical figures for M8 bolts found on the net...

(source: https://www.engineeringtoolbox.com/)

Mmmmm… yes and no. 
everything JTHayer pointed out above rings true.  What’s your “good authority?”, a Yamaha SM English/japanese translation specialist out of George or California?

what you’re not considering  @AndyW is the fact that the sprocket nuts are special - I think Yamaha calls them a U-lock nut.  If they are REPLACED and tightened in several stages following the pattern in the book, they will take a torque value of 50-55 lb/ft with a 3/8 wrench. 40-50 nm is far too low IMHO (the naysayers will chime and tell me I’m wrong here and 40nm is ok, but I don’t agree with them so we will agree to disagree, just like the political climate in the US currently, sound good?)

if it is a misprint, 59 nm=43.516 ft lb and Honda usually recommends 43-45 ft lbs with a nylock style nut IIRC  for a rear sprocket but so there’s that to consider as well.

The fastener chart you listed takes the “grade” of the fastener into consideration but not the type. 

I will also mention that junk torque wrenches and common sense can be off enough to wreck a fastener. All of mine are digital SnapOn techangle torque wrenches, and I use a 3/8 wrench not a 1/2 wrench for that particular job. 

I would fault Yamaha for not being a bit more clear about some of their procedures and when to use a new fastener vs re-using. They are also NOT written or organized for a home mechanic, but for experienced techs. Honda and H-D SM are much more “user friendly” in the way that they are written and organized. 

YMMV and IMH(P)O,

skip

Edited Monday at 03:04 PM by skipperT

[AndyW]

Thanks for the input Skipper, great post, appreciated 👍 

All sounds authoritative... can I ask about your qualification/experience/sources?

My 'good authority's is in the nuts and bolts industry..... and he happens to own an MT09.

I should have also said, that unable to source OEM sprocket nuts, I've gone for Ti nyloc nuts.

[piotrek]

I have not had any issues with torque values listed in the FJ-09 Service Manual, including the sprocket nuts and the rear axle nut. I think it's important to clean fastener threads well where dry torque is specified. Some threads/fasteners are meant to deform/stretch slightly to provide the required clamping force. I have been known to re-use here and there. YMMV 😜

Chain slack on the Gen-1 FJ was bananas... and it was corrected in later model years. Torque values generally remained similar through the years.

[skipperT]

11 hours ago, AndyW said:

Thanks for the input Skipper, great post, appreciated 👍 

All sounds authoritative... can I ask about your qualification/experience/sources?

My 'good authority's is in the nuts and bolts industry..... and he happens to own an MT09.

I should have also said, that unable to source OEM sprocket nuts, I've gone for Ti nyloc nuts.

You’re welcome. 
Ah. Ok, so he’s obviously familiar with different fasteners and their materials, as you mentioned. (I was looking for inside info on potential SM corrections, but I don’t think we’ll ever get them.)

As @piotrek mentioned the SM editions haven’t changed much over the model year run except for the minor changes from FJ to 2017 FJ to Tracer 900/GT to Tracer 9GT. I think the 21-23 (?) and certainly the new GT+ models have the most significant changes.

you can ask… but I won’t post publicly about that.

interesting nut choice. A dab of blue loctite is never a bad idea. I don’t know how Ti fasteners compare with other types re torque value, that’s interesting too. The only oneA I’m familiar with are newest Gen R1 engine case cover bolts, which are one time use and cost like 10 bucks apiece. Had to throw them all away during the transmission procedure/recall of the 2015 (16?) R1 engines. Nutty. 
-Skip

[AndyW]

I will indeed use some threadloc👍 ...doubles as anti-seize and stops bimetallic reactions.

The nuts I've bought have been tested at 60Nm.

I'm going to go for 50Nm and check them regularly for a while to see that the nyloc/threadloc is doing its job.

I can't fathom any any reason why the sprocket / sprocket carrier interface lower torquing would be detrimental.... I'm assuming Yamaha's figure is purely set (as a belt and braces figure) to ensure the nuts don't loosen.

[skipperT]

5 hours ago, AndyW said:

I will indeed use some threadloc👍 ...doubles as anti-seize and stops bimetallic reactions.

The nuts I've bought have been tested at 60Nm.

I'm going to go for 50Nm and check them regularly for a while to see that the nyloc/threadloc is doing its job.

I can't fathom any any reason why the sprocket / sprocket carrier interface lower torquing would be detrimental.... I'm assuming Yamaha's figure is purely set (as a belt and braces figure) to ensure the nuts don't loosen.

Only detrimental just like any fastener coming loose can be dangerous - and those nuts are spinning around on the rear tire of course. I just don’t like to take chances with those kinds of things, too much liability. So when I see guys using 40 nm, that’s MUCH less tight IMHO than 58nm, I just shake my head cause I know what can happen. (This is assuming Yamaha made a mistake in the translation. And that’s a big assumption!)

who knows what Yamaha engineers were worried about? 
-Vibration through the driveline, due to the firing pulses of a triple and driveline lash? Maybe heat transfer (Although I can’t imagine it being much higher than any chain final drive). -Using a stud instead of actual bolt due to space limitations and wheel/carrier design maybe? -cost/quality of the stud/nut and it doing “the job”? Who knows, but I’m sure there were lots of consideration that most of us don’t think about unless we’re mcy designers/engineers.

as mentioned, Honda SM specs are 43-45 ft lbs (roughly 58nm) for most rear sprocket nuts in that same thread size (ie CBR’s) so I think that’s why the “consensus” arrived at those numbers. The design of the studs/bolts and nut type does vary by model across motorcycles in general. 

we’ve probably beaten this to death by now lol. 
Just IMHO and YMMV,
-S

Edited Tuesday at 03:07 PM by skipperT