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199B Yokes


bondy
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Wow 15 ft/lb that is over 20Nm ?

The bolts to the yokes are allen screws in M6 diameter with 1,0mm threads and with grade 8.8 the maximum torque (according DIN 912) is given 10,2 Nm = 7.5ft/lb.

As they are bolted in aluminium I wouldn't use so much tension, the handbook of my KTM states 5 Nm for M6 bolts, were many screws are bolted i aluminium, which I think is OK if you realy need a number.

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Agreed 7.5ft/lbs is correct. 15 and you'd break the bolts. Bondy torque specifications for bultacos are the same as any other model new or old. Proper torque values are derived from the grade of bolt, and the diameter and thread pitch of a bolt. A 6mm bolt on a bultaco will have the same torque as on a modern honda. I will say the torque settings on engine cases and heads are critical. As are fork yolks. Distortion of the fork tubes is very possible if over torqued. Bottom line use a torque wrench on all critical fasteners. Your elbow doesn't know but your torque wrench will. !!!!

Steve

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Hello Bondy, There's so many things to consider...are they the original bolts, which would make them 40years old, have they maybe been overtighten at some time in thier life. Maybe they've been changed, if so are they the correct quality....loads of unknowns. Herewith.......www.nutsboltsandthings.co.uk/information/faq&topic=2 This chart gives torque settings for size and quality also dry or lubed thread. There is one other consideration, let's call it 'mechanical feel'...years of experience, and the 'feel' of a stretching bolt.....this wouldn't really be a consideration, if the bolts were virgin, the threads lubed and the torque wrench accurate.

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Agreed 7.5ft/lbs is correct. 15 and you'd break the bolts. Bondy torque specifications for bultacos are the same as any other model new or old. Proper torque values are derived from the grade of bolt, and the diameter and thread pitch of a bolt. A 6mm bolt on a bultaco will have the same torque as on a modern honda. I will say the torque settings on engine cases and heads are critical. As are fork yolks. Distortion of the fork tubes is very possible if over torqued. Bottom line use a torque wrench on all critical fasteners. Your elbow doesn't know but your torque wrench will. !!!!

Steve

Distorte the leg, how much force are you using ?

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I wasn,t trying to give you a wrong answer bondy,but reading the other replies 15 does seem too much.I might have mis-interpreted my manual.I was going by what it says under forks,the last setting,'bottom bracket -stanchion tube clamp." I did not know they where threaded yokes so I,m really glad the others chimed in because my answer might have caused you some troubles. I have always done it by feel so I guess I need to think more and research more before I answer questions like this! Thanks to all for a correct answer :thumbup:

Edited by scot taco
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