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Author Topic: Head and Valve Torque Values  (Read 907 times)

Crossrodes

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Head and Valve Torque Values
« on: June 11, 2009, 11:18:05 AM »
I've read in various places that you can't be sure that your manual has the correct torque values.  I've looked here for a chart and the only one that seems to be mentioned is on a website that I can't access (it's not on-line).  

I'm sure that someone here has the correct values for my '79 R65...or are the values in the Clymer manual correct?

Offline Barry

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Re: Head and Valve Torque Values
« Reply #1 on: June 11, 2009, 11:30:33 AM »
Can't remember where I got this chart but it must have been off the net somewhere.
Barry Cheshire, England 79 R45

Offline nhmaf

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Re: Head and Valve Torque Values
« Reply #2 on: June 11, 2009, 06:27:04 PM »
The 25 lb-ft torque value for the head nuts seems fine.   The valve adjustment nuts are probably OK at 15 lb-ft as an upper limit, just be careful to not strip threads - if it seems good and tight and you're at 12-ft lbs on those, I'd say stop there - they only need to be sure not to loosen up.

Some of the other values in the chart I do question somewhat. For example, the front fork oil drain bolts will very likely start to pull thread in the aluminum alloy sliders if you crank them up to 12 lb-ft of torque - many of us use 10 lb-ft as an upper limit, or as little as possible.  I also tend to torque the 12-point driveshaft to output shaft bolts (inside the rubber swingarm boot) up to at least 30 lb-ft and likely more (I can't get my torque wrench in there, and I'm in 'frugal' mode lately so haven't bought an adapter and use the "goodentite" method on those - they are supposed to stretch, after all..    10 lb-ft is plenty on the center "acorn" valve cover nut - again it will be a major nuisance if you pull a stud, and those (2) side nuts do must all of the valve cover holding work anyway. Many of the other values in the chart seem reasonable.
Airhead #12178 ? BMWMOA #123173 ?BMWRA #33525 ?GSBMWR #563 ?1982 BMW R65LS ?1978 BMW R100/7 1998 Kawasaki Concours

Offline Barry

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Re: Head and Valve Torque Values
« Reply #3 on: June 12, 2009, 02:35:40 AM »
I'll see if I can edit that chart with your suggestions so that we end up with a real life set of values.
Barry Cheshire, England 79 R45

Offline Mike V

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Re: Head and Valve Torque Values
« Reply #4 on: June 14, 2009, 11:16:46 AM »
Barry & Crossrodes,

The Torque Chart is mine and comes with many caviets, obviously.  Torque values are always a subject of debate and care needs to be taken. The chart was created specifically for my 78 R100/7 as a composite chart to be used in the shop. The chart was forwarded and reviewed to the Airhead LIST and the main Guru's approval. Some of these items I personally never use such as acorn nuts and valve cover nuts. Nor do I torque spark plugs or the more sensitive areas such as point plates and ATU nuts.  I think it's best to develop a feel for these more sensitive applications and less is always better than over stressing problimatic areas. I would suggest using an inch pound wrench for values that fall below 8 to 12 foot pounds. I would check with the forum guys for the 650's and maybe cross reference multiple sources and manuals. You may find a large deviation from different references as I did and always be careful of conversions from ft-lb to Nm, and vise versa. There are published errors out there!  I'm restoring an 81 R65 at the moment and have used this chart with no problems so far - use it at your own risk and any skepticism on your part can be beneficial at times. If any of you would like the original Excel file to revise for your own use and application contact me off-forum and I'm happy to send it to you.

Good Luck,

Mike V. / San Diego
mvtv@cox.net
Mike V. / San Diego
'78 R100/7 (original owner)
'81 R65 (fully restored)