Loosen them five minutes on the clock face.

Opposite order from tightening sequence, outside working in.

You can torque with a spanner and a spring balance (the thing you weigh fish with). 18 pounds foot is 18 pounds force on a one foot long wrench, or 36 pounds on a six inch radius from the centre of the bolt. The indicator should reach the desired point on the scale while the bolt is moving.

Do it after your first run of a few miles.

Again at 100 miles. If the bolts take a tighten, do it again at 300 miles. /QUOTE]

 

Loosen them five minutes on the clock face.

Opposite order from tightening sequence, outside working in. /QUOTE]

So, once a bolt is loosened, is it immediately re-torqued or loosen them all and then re-torque them per the service manual? Does it matter?

S

 

htown,

the only bonnie that you list ( assuming that this is the composite in question) is a T140E
what bolts can't you get a torque wrench on?

i have no problem with my 79, apart from the PITA of removing the tank etc

 

Actually, it was a general question and I also had in mind the Commandos. The rear bolt on them is almost impossible to get a torque wrench on.

 

ah!!

afaik you can use a ring spanner of a given length and compensate,
like a "crow's foot"

 

C=d (A+B) DivA.

C=Torque wrench setting
D= Torque setting of bolt
A= torque wrench length
B= centres of spanner extention.

Hope this helps

 

I torque the head down, start the bike and warm it up for a few minutes, let it cool down and re-torque the bolts. Then check them again after 60 miles or so. Found I've never had to touch them after that. I don't loosen them off before re-torquing.
Cheers Mossy

 

Not turning the bolts back a little bit before re-torquing is wrong. No argument.

 

TT, if you were leaving it a few months before re-torqueing I would tend to agree. But as I do it within a couple of days and use Molybond GA-50 as a lube on the threads they don't have time to seize up therefore don't require loosening off first. They always nip up a bit more before reaching the set torque.
That's the way I've always done it and never had problems with head gaskets leaking.
Cheers Mossy

 

I recommend do the bolts 1 at a time. I usually do them in order of the torque pattern. Always back off 1/8-1/4 turn or so. You'll feel it get looser so you know it will then be able to pull tight upon torqueing. We don't want static/starting friction to effect reading. Then come up to torque smooth even pull. Never jerk the torque wrench. I've never used composite gasket though, just copper. I always recheck valve adjustment after head torque as any compression of gasket will effect valve adjustment.
For an experiment after my last head gasket (.080" thick, normal is .050) I decided to check valves before & after. Compared to new old stock gasket, my .050" gasket had compressed only .001-.002" over time at most.
I always mark head bolts, nuts with felt pin so I can see the amount of rotation before & after. My procedure was after 1 warm up & 10 miles, then cooled overnight, retorqued. I didn't check valves. Got a fair amount of extra turn of bolts/nuts. Next torque was about 200 miles, tightened valves about .001 at most. little bit more turn of bolts/nuts. The next torque was 1000 miles. Practically no change at all if any at all in valves & bolts/nuts didn't hardly change position. not even 1 deg. Now I will just do before every 3000 mile valve adjustment.
After 34 years storage & only 1 retorque after the original gasket was replace, (6000 miles on that gasket) the bolts took quite a bit of turning.
I was originally concerned the .080 gasket might squish out or migrate, but hasn't so far. Also the head doesn't seem to be compressing or indenting at the head bolts/nuts. The washers inside the rocker boxes are the same diameter as the lower diameter of the allen nuts. Next time I think I'll go with larger washers there if possible.
I was checking valves every 1000 miles due to worry of unleaded fuel wearing seats. Turns out the valve adjustment doesn't hardly change at all. I guess that means the seats aren't wearing or... cam wear is matching seat wear.
The gasket that had 6000 miles on it wasn't blown. I took top end off to reseal tappet blocks. In retrospect with it taking so much turning of bolts/nuts after not torqueing for 6k miles I feel it would have been better to retorque more often. That gasket had a very slight oil leak for some thousands of miles. Retorquing reduced the leak, but didn't eliminate it all together. Again, a very slight leak, no drops, just a little sweating.
Regarding composite head gaskets on Mercedes Benz cars for sure retorquing can reduce leaks. Even the ones with stretch bolts benefit from a retorque. Those are suppose to compensate for expansion etc. but they can loose some tension. You have be mindful of stretch limit of bolt though! But you can take bolt right out (only 1 at a time) without problems. I've wondered how these would be for a Triumph?
On the older cars with non stretch bolts we always retorqued after 1 warm/cooling cycle. That always worked good for us. Personally I'd retorque the Triumph composite head gasket if I had one.
Don