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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: kris on March 21, 2015, 09:22:22 PM

Title: Triple Tree Torque Specs/ A Discrepancy....
Post by: kris on March 21, 2015, 09:22:22 PM: Hello all,
I have just re-installed the forks on my K100. I have the torque spec cheat sheet off this site which states 42 NM for the upper pinch bolt and 21 NM for the lower. The Haynes manual says the opposite....21 upper and 42 lower. Can anyone tell me which is correct? I remember Chris Harris questioning the 42 NM on the shallower head lower bolts. I don't want to strip anything out at this point. I am in the high 30's NM on the uppers at this point (probably close to 40) but it just feels like there is a fair bit to go and I don't want to screw it up!!

Thanks!
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: kris on March 21, 2015, 10:05:34 PM: I just checked the fiche for bolt sizes. The uppers are 8 mil and the lowers are 10 mil. From that standpoint I guess 21/22 NM for the uppers makes more sense and 42 NM for the bigger lower bolts also has a ring of sense to it. Still wouldn't mind some back-up....
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: The Mighty Gryphon on March 21, 2015, 11:42:05 PM: Clymer says 19-23 upper and 40-46 lower.

BMW says 21-23 upper and 40-46 lower.
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: Elipten on March 22, 2015, 12:08:22 AM: The sheet of site is incorrect and if you use it you will stretch the bolt or worse snap the bolt. Follow the BMW manual,always do your due diligence as why trust someone else who typed it up.
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: kris on March 22, 2015, 12:39:57 AM: Thanks guys. I backed off the uppers and went with 22 NM. Lowers got around 43 NM. Should have checked bolt sizes and drawn my own reasonable conclusion. No damage done, as far as I know.

Take care!
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: Elipten on March 22, 2015, 06:36:41 AM: Check that uppers are not stretched, use a micrometer on the non threaded portion of the bolt. This is seriously dangerous error on that sheet. I believe I posted this last year, but can't recall
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: johnny on March 22, 2015, 09:05:22 AM: gimme a link to where the specs are wrong so we can fixt it...

j o
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: detbmw on March 22, 2015, 01:45:56 PM: Quote from: johnny on March 22, 2015, 09:05:22 AM
gimme a link to where the specs are wrong so we can fixt it...

j o

Johnny,

I think they are talking about the pdf file here: http://www.motobrick.com/index.php/topic,4949.0.html (http://www.motobrick.com/index.php/topic,4949.0.html)
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: F14CRAZY on March 22, 2015, 03:06:55 PM: the oil pressure sensor spec is also too high on that pdf
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: johnny on March 22, 2015, 04:37:09 PM: rodger...

that pdf is on vacation... will return to work once it getts its mind sorted out...

j o
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: Elipten on March 22, 2015, 08:07:39 PM: Thanks Johnny. You saved a trusting soul from a huge mistake
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: johnny on March 22, 2015, 08:16:07 PM: i donts use a twerk wrench... i twerk everything till it feels like its gonna strip then back it off an eighth of a tern...

and to adjust my valves i run a tank of half no corn ethyl and half techron... near the red line of course...

j o
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: Elipten on March 22, 2015, 10:20:40 PM: LOL
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: kris on March 22, 2015, 11:13:49 PM: Thanks gents for your attention to this matter. I might (probably will) simply replace the two upper bolts. Better safe than sorry on those....don't think I cranked them that hard. As I think I mentioned likely into the high 30's NM. Good German steel should be able to handle that, don't you think?? :euro
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: Elipten on March 22, 2015, 11:19:55 PM: Specifications exist for a reason. Cheap to replace the bolts to be sure, your life I hope is worth 2 bolts.
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: kris on March 22, 2015, 11:24:22 PM: Agreed. Thanks.
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: enialb2 on June 23, 2016, 12:07:50 PM: Yeah... I just snapped my upper pinch bolt while following that handy pdf spec sheet. 43Nm is apparently too much for it to bear. $&@%!
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: Chaos on June 23, 2016, 12:18:09 PM: never used a torque wrench on pinch bolts, just common sense. with bad torque specs floating around that may be a plus. assuming, of course, you have good common sense.
Title: Re: Triple Tree Torque Specs/ A Discrepancy....
Post by: mw074 on June 23, 2016, 12:34:05 PM: Front axle pinch bolts are also known for breaking if over tightened. Caution on re-assembly.