torquing Head bolts

Skelly · May 3, 2014

I'm replacing the head gasket on my 74 850. No problem to find the torque settings, but I'm wondering to make sure the torque is right on the cylinder base nuts. It was all I could do to get on theese with a boxed of a wrench. There is no way to use a socket and torque wrench on them.

Any ideas or to one just go by feel ?

pete.v · May 3, 2014

Skelly said:
I'm replacing the head gasket on my 74 850. No problem to find the torque settings, but I'm wondering to make sure the torque is right on the cylinder base nuts. It was all I could do to get on theese with a boxed of a wrench. There is no way to use a socket and torque wrench on them.

Any ideas or to one just go by feel ?

I am sure 99% of us go by feel. Just don't over do it and check them once in a while after geat cycles.

Rohan · May 3, 2014

Doing it by hand is perfectly acceptable, if you don't overdo it, and can keep tham all reasonably evenly torqued.
Its not exactly a critical area.
It was mentioned here recently that no base gasket is involved with an 850, so there is no gasket to compress either.

It is possible to attach a torque wrench to the spanners/wrenches required for this though.
Its a matter of finding the right chain of 1/2" drive bits to cobble something up.
Someone hopefully will show a diagram of what is required, its out there, somewhere.

Remember that if you add length to the total length of wrench, then the applied torque needs to be reduced.
i.e. an 8" wrench at, for example, 20 ft/lbs if made 16" long (double) needs to be 10 ft/lbs on the torque wrench.
If the torque wrench is set at a full 90 degrees to the attached wrench, then the torque is kept at that 20 ft/lbs

Hope this makes sense.

That might be check after some heat cycles (above).

Fast Eddie · May 4, 2014

Skelly said:
I'm replacing the head gasket on my 74 850. No problem to find the torque settings, but I'm wondering to make sure the torque is right on the cylinder base nuts. It was all I could do to get on theese with a boxed of a wrench. There is no way to use a socket and torque wrench on them.

Any ideas or to one just go by feel ?

You can easily practice your 'feel' Skelly...

Try tightening up some nuts / bolts held in the vice (or whatever you've got) and measure them with a torque wrench. Tighten them to different amounts and try and guess the torque you'll achieve. Also, fit some to the correct torque, with the torque wrench, then using your normal wrench, see how much force you have to put into to to 'just' make it turn. You'll soon get your 'feel' plenty good enough to be able to tighten your base nuts properly.

mschmitz57 · May 4, 2014

You can buy a torque wrench adapter that allows you to use any combination wrench.
I bought the Motion Pro adapter and really like it.
I was amazed how far off my "feel" was when I checked my work with a torque wrench.
I was consistently under torquing the head bolts when doing it by "feel"

http://www.motionpro.com/motorcycle/par ... MgodChgAhg

Mark

Nigeldtr · May 4, 2014

As fast Eddie says, develop the feel for the bolts and "stretch" you can't get a torque wrench in there anyway. PS, the advice of checking after 50 miles and then again after say 150 miles is spot on. I was really surprised how much the gasket compresses after the initial tightening and running :shock:

Fast Eddie · May 4, 2014

Nigeldtr said:
As fast Eddie says, develop the feel for the bolts and "stretch" you can't get a torque wrench in there anyway. PS, the advice of checking after 50 miles and then again after say 150 miles is spot on. I was really surprised how much the gasket compresses after the initial tightening and running :shock:

Just for clarification, Skelly has '74 850... My understanding is that these should be assembled WITHOUT a base gasket...!

Nigeldtr · May 4, 2014

I was referring to the composite head gasket. My 850 has a compression plate and gaskets either side, under the barrels as the inlet valves were touching the pistons (a different story), also needed to be nipped up.

Sorry for the confusion.

john robert bould · May 5, 2014

Bolt tightening...oiled or not is the question?

Hobot · May 5, 2014

I going by feel on everything but rod and crank fasteners put anti-seeze on so mainly I'm feeling the pure bolt stretch sense after initial distinct seating to eliminate as much bolt shaft twisting friction t-wrench and mm's torgue confusion. I retorque by just twisting tighter and rarely back off first as the ones I find that need retorque move tighter w/o backing off first. Do not forget to check the cradle engine fasteners every few head and barrel nip ups. Ugh.

john robert bould · May 5, 2014

Dry bolts have greater friction...thread and head /washer friction...stretch is less for the given torque..dip the bolt in Slick 50 and get another 1/2 turn with the same wrench setting.

Hobot · May 5, 2014

Hm I worry if there's a possible issue of hydraulic lock in hole if applying thick film of thick oil?

john robert bould · May 5, 2014

I didnt say fill up the hole :lol: and the dipping should be taken as example :roll:

Matt Spencer · May 5, 2014

john robert bould said:
Bolt tightening...oiled or not is the question?

dont do em dry . most motorcycly stuff the fingertips are usefull , a few at a time .
I suppose outdoors in Siberia a tourque wrench might be usefull , if its kept warm .

Hobot · May 5, 2014

No way I'd imply you'd on purpose leave extra oil John but I'm very familiar with various engine honey's Lucas to STP to off brands to know unless wiping off its left on layer will be thicker than thread spaces and maybe hole bottoming. As you've not reported this I guess its just a non issue worry of me only. If ya really want best oil type thread lube nothing beats real castor bean oil for easing in interference fit parts that then congeals to glue em fixed.

Brooking 850 · May 5, 2014

Hi all, you would have to think these guys know their stuff!!!!

http://arp-bolts.com/p/arpultratorque.php

Regards Mike

gripper · May 5, 2014

If you use a 1/4 whit combination spanner (wrench) that's one with an open ended end and a ring on t'other, You should find that a 1/2" square drive torque wrench will fit in the open ended jaws. Provided you maintain the initial angle between the spanner and the torque wrench at 90 degrees, you will get the torque you have set on the torque wrench. It's a bit of a fiddle but it is possible. Make sure that you thin down the ring of the spanner so that there is nothing binding against the barrels.

john robert bould · May 6, 2014

good link Mike!

Brooking 850 said:
Hi all, you would have to think these guys know their stuff!!!!

http://arp-bolts.com/p/arpultratorque.php

Regards Mike

htown16 · May 6, 2014

use the German spec "gudentite".

Skelly · Sep 21, 2014

Hi all,

Sorry it has taken so long to get back to this thread.

I just wanted everyone to know that i did torque the bottom head bolts by using the closed end of the wrench and the nut and placing the torque wrench in the open end. Keeping it at a right angle to the wrench I tightened it to 20 ft lbs as per spec.
After about a 100 mile ride, I went back and re torqued all of the head bolts. That has been at least two weeks ago now and I've probably put another 500 miles on the bike. So far no leaks.

torquing Head bolts

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