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Caution with Manufacturer torque values


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Sorry if this has been discussed before but found this interesting. 
This article discusses the effect of torque settings depending on whether the thread is dry or lubricated.
It basically says that if the thread is not dry you should reduce the torque by as much as 50%.
I try to follow the manufacturers toque settings as much as possible but often these values 'feel' over tight.
I wonder if this could explain why some people are having issues with the rear axle nut for example.
How many of the bolts we tighten are truly 'dry'? I know the oil drain plug never is!
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My professional opinion on this is that when the service manual is written, the engineers take into account what status the bolt will be in when the component is re-assembled. Ie, if it calls for blue loctite/anti-seize/dry/spit/whatever on it then the torque value listed will reflect that. If the bolt or nut should be replaced, same.
People strip fasteners because they don’t follow procedures as written, or they second guess the procedure, or they use inferior or the wrong torque wrenches.
I own 7 torque wrenches, and the 3 I use most often cost me over $1200 US. I don’t buy them at Sears, I don’t drop or beat them, and I calibrate my 1/4” which is used the most and NEEDS to be the most accurate because it is frequently used in the 5-8 ft lbs area, every couple years.
I’ve NEVER stripped an oil drain plug and I’ve can’t even count how many I’ve tightened to 22-31 ft lbs. Covered in oil, or wiped dry. If I break or strip a fastener, it’s usually because the last guy F-ed it up or I cross threaded the bolt and caused the issue. Once in a while I run into a bad set of threads in a case part due to poor manufacturing or from water intrusion.
The axle nut issue is probably caused by the alloy of the materials used to make those components not agreeing with each other in some way, but I’m sure an engineer would know better than I.
Again, torqued to 105-110 ft lbs for years and never had a problem.
Use the right tool for the job and follow the book. Simple as that.
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Yes, a lot of the values in the manual have been discovered to be wrong.
Disagree 100%.  
Give me some examples. Who said that they’re “wrong” and what was the reasoning?
When I say values in the manual, I'm talking overall values printed in the manual, chain slack, replacing spark plugs at 8k, very high torque values (sprocket, axle etc). 

***2015 Candy Red FJ-09***

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I am so glad this has come up again. Please everyone look at the referenced link above, (similar to others I have seen) as it has engineering value and all nuts or bolts that have some kind of lubricant on them should not be torqued to Yamaha specified values unless you have cleaned them with a solvent and they have no lube left on them. Reference:  Yamaha Service Manual for FJ-09, page 2-13 specifies torque values and notes that "unless otherwise specified, tightening torque specifications require clean dry threads"
One might note that for a 17mm nut (oil drain is 17mm bolt head) general tightening torque is 40 ft-lbs.  The specified tightening torque in the manual is 31 ft-lbs.   One might assume this adjustment 40 to 31 was made due to the fact that the bolts was assumed to have oil on it, but it isn't written, specified so or shown on 2-14 as being oiled.  Also, in the schedules pages 2-14 thru 2-24 all nuts and bolts needing a lube, whether Locktite or engine oil are noted.  People have had problems with oil plugs tightened to 31 ft-lbs for years at the number Yamaha specifies, so why flirt with stripping the threads when reducing the torque works?   (I use 27 ft-lbs and have never had a problem in over 300,000 miles (FJRs and FZ - FJ-09s)).

Ken, Candy Ass L.D.R. Sleeps 8 hours
(2)2005 FJR1300abs:  230,000 m
2015 FJ-09:  114,000 m (Replaced engine at 106K)

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Betoney- Manufacture replacement intervals are a guide. I agree that plug replacement at 8k is premature on this engine, but Yamaha hasn't gotten with the program and blown that out to 16k ala Honda.
Chain slack has been debated many times over the years.
Disagree on axle and sprocket torque. Maybe we will have to agree to disagree. As I indicated, I've NEVER had an issue following the book. 
People having an issue replacing rear sprockets and not seeing the correct torque are having an issue because they are re-using a nut that should be replaced once it is loosened. Yamaha should really correct that to "always replace".
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Recommended torque value for the oil drain plug you mention should not be based on the 17mm bolt face. It's based on the thread pitch of the fastener which is actually a 14mm thread pitch (see page 2-14). The thread pitch of the fastener isn't mentioned at all in that chart you referenced. That chart is derived from the measurement across the flat area of the nut or bolt (ref A and or B)
Honestly the chart isn't an accurate way to calculate a torque value. Thread pitch is best followed by common sense.
For example the oil filler cap listed on page 2-16 is a 20mm thread, which should be hand tight, or as Yamaha lists 1.1ft/lbs. It's also made of plastic! The composition of the threads or fastener also affects the value
I would only follow the chart you referenced if a nut/bolt tightening torque isn't listed elsewhere in the service manual.
To repeat: I've NEVER stripped a 14mm thread pitch engine oil drain plug tightening to 31ft/lbs. Why? Because I use an accurate torque wrench and I ALWAYS REPLACE THE CRUSH WASHER.  
All those stripped drain plugs you've cited (probably from reading forums) have happened because people don't think that the crush washer is 1 time use. Oil on the threads didn't cause the drain plug to strip, its because the crush washer was re-used. The 31 ft/lb recommendation takes into account the torque required to collapse a new crush washer. Do you replace yours every time? If not, then your recommendation makes sense. 
Here's some other examples why you should follow the book and not always go by thread pitch or head measurement:
-Many Yamaha ATV's and SxS's use the same oil drain plug in the fill point of the front or rear differentials. Same 12mm thread pitch, but the case of the diff is a different material. So even though the crush washer should be replaced, the recommended torque on those machines is 16-21 ft/lbs because the threads aren't as strong.
-Same for final drive drain/fill plugs on FJR's, and V-Star 650's and 1100's, 16 ft/lbs is recommended.
If you follow the chart you reference BEFORE attempting to follow the published torque value, you will probably wreck a lot of fasteners.
I have found typos in Yamaha torque values over the years however. Usually a decimal point is in the wrong place on a component diagram, or when the Nm value was converted to Ft/lbs it wasn't calculated correctly. 
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