'71 750 Commando head fasteners-torque

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'71 750 Commando.Need some help on torquing the head. All the nuts and bolts are the same 1/4 W, 5/16 BSP. Shop manual says torque 5/16 to 20 ft/lb, 3/8 to 30 ft/lbs. Which ones are 3/8? Does the size refer to the stud and bolt shanks?I have nine fasteners. Could someone tell which are which? Or are they all 5/16?
Thanks
Doug
 

lcrken

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The size refers to the stud and bolt diameter. The two studs in the front of the head with the nuts visible looking down on the top of the head, are 5/16". The other seven bolts and studs are 3/8".

Ken
 

L.A.B.

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Douglass Harroun said:
All the nuts and bolts are the same 1/4 W, 5/16 BSP. Shop manual says torque 5/16 to 20 ft/lb, 3/8 to 30 ft/lbs. Which ones are 3/8? Does the size refer to the stud and bolt shanks?I have nine fasteners. Could someone tell which are which? Or are they all 5/16?


All the head fastener hexagons were made 1/4" W, (or 5/16" BSF) size, regardless of their actual bolt diameter or thread type. So as Ken said, go by the bolt diameter, not the size of the hexagon.
 

lcrken

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ludwig said:
shouldn't that be 10 bolts /studs ? .( 8 times 3/8 and 2 times 5/16)

Indeed, it should be 10. I think I left out the center head bolt while counting in my head.
 
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ludwig said:
shouldn't that be 10 bolts /studs ? .( 8 times 3/8 and 2 times 5/16)

Yes, 5 bolts, labeled 1,3,4,5,and 6 in the manual - all 3/8 thread

3 nuts, labeled 2, 7 and 8 - 3/8 thread, fastening to studs in the head

2 nuts, labeled 9 and 10 - 5/16 thread, fastening to studs in the cylinders

Tightening/torquing order is 1-10.
 
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head fasteners

"The size refers to the stud and bolt diameter. The two studs in the front of the head with the nuts visible looking down on the top of the head, are 5/16". The other seven bolts and studs are 3/8".

Ken
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Thank you all very much. Now I need a way to torque the rear center and two forward nuts. I can get a short thin ring spanner on them , will see if I can rig something to allow a torque wrench to be used, maybe put some nuts on a bolt together through the free end and put a socket on top? What do you do?
Doug
 
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