torque setting

[Bill Conquest]

Hi - I'm about to check my valves on my '79 r65 & am wondering if anyone can advise me on the correct torque setting for the cylinder head bolts..i've been seeing various numbers & am a little afraid to over or under tighten them..it's never been done on this bike since i've had it..
Thanks, Bill

[Bengt_Phorqs]

Bill, according to my Clymer manual the Maintenance and Tune Up Torque Specifications for the Cylinder head nuts are 35-39 N-m and 26-29 ft lbs.  Valve adjuster lock nuts are 11-22 N-m and 8-15 ft lbs.

[Bill Conquest]

Thanks Bengt forks..are my valve setting numbers o.k. ,too? (.004 - .008)

[montmil]

Bill, the last BMW technical service bulletins listed the valve clearances just as you posted. The larger valve lash clearance on the exhaust valve allows the valve to remain on the seat for just a nano-second longer, allowing for additional heat transfer.

If you were to error on the cylinder head torque, do so on the lower end. Pulling a cylinder stud is a very real possibility. Be cautious.

[Dave 2]

If you were to error on the cylinder head torque, do so on the lower end.  

From several members's advice, including Mr. Monte, I have started to use the lower torque values. It is true my bike is "In Restoration Mode" and is not completed, however I have faith in the forum's wisdom that nothing will self destruct with the lower settings

[Mike V]

Bill,

I would use the lower head bolt torque values also.  Personally; I use a maximum of 25 Ft-lb.  And in 3 stages; 17,20,25 Ft-lb.

Just my personal opinion.

-Mike V.

[Bill Conquest]

Thanks much,everyone, everyone for the info & advise,
Bill

[Barry]

I chicken out at 23 ftlbs and don't have a problem. Also I don't torque the heads unless I have a good reason to like adjusting the rocker end clearance. Certainly I do not do it at every valve adjustment.  There is no reason for the head gasket to keep settling down year after year so no point in asking for trouble by torquing the heads.

Within limits actual valve clearances are a personal choice and you can tune the engine response in some small degree by the settings used. Close clearances for top end revs if you are a racer, wider clearances for low end tractability and economy. The effects are small but readily detectable because you are effectively adjusting the valve timing and lift.  I'm running very tightly set  6 and 10 thou (probably 5.5 and 9.5 thou) with no noise increase. What ever clearances are used, striving to have them as close to the same for left and right pot is more important than the actual value.

[tvrla]

I'm with Barry on this - don't pfutz with the head studs unless it's absolutely necessary!

I run all my bikes at four and eight, and torque to 25 ft/lbs.

[Justin B.]

On my last couple top-end jobs I've used 20 lb/ft with no ill effects...

[Bill Conquest]

Thanks.. I think i'll just leave 'em alone as there doesn't seem to be anything wrong there..though I do have some seepage at the valve guide seals underneath..
Bill

[montmil]

Thanks.. I think i'll just leave 'em alone as there doesn't seem to be anything wrong there..though I do have some seepage at the valve guide seals underneath.. Bill

Doubtful the push rod tube seals are weepy due to cylinder stud torque. The rubber bits will become hardened from age and engine heat. I have a fresh foursome waiting for installation on the '81 R65. Trying to decide if and when a valve job should be included. Either way, the heads and barrels will be opened up.

[Bill Conquest]

Yes, i've been tapping on the guide rings to tighten the seals & putting off the inevitable..i'll be following your progress, Monte, to learn from!
Bill