Tighten the cylinder head

pete4000

Active Forum User
VOC Member
Hello everyone,

I'm about the reput my pistons, muffs, cylinder heads on my shadow engine, and tighten the heads at the normal torque of 4.15 kg. I would like to know if it is necessary to retighten my cylinder heads after running a hundred miles with the bike ? Is it necessary as it is current on most classic bikes ? The Richardson says nothing about that, only to tighten the heads at a torque of 4.15 kg.
Thanks for your answers.
Pete
 

nkt267

Well Known and Active Forum User
VOC Member
Most people I have met re-tighten the head bolts after a few hundred miles.I certainly do..John
 

bmetcalf

Well Known and Active Forum User
VOC Member
Torque to us old guys is in pounds-feet, so I don't know what 4.15 kg relates to. It is only 9.13 pounds-feet if applied at 12 inches (400mm) from the bolt centerline, so a bit low from usual torque figures.
 

stumpy lord

Well Known and Active Forum User
Non-VOC Member
In english the recomended torque loading for cylinder head nuts is no more than 30 foot pounds or 4.15 kg.-meters. to go higher can cause the piller cast into the cylinder heads to collapse.
stumpy lord
 

bmetcalf

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VOC Member
I should have put more thought into my question. If the units are kg-meters, the number is in the right range.
 

Don Morris

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VOC Member
My memory is a little vague on this but I believe that Velocette's practice was to re-torque the cylinder head nuts 24 hours after the intial assembly in the factory.
 

Len Matthews

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VOC Member
Re checking the head nuts is important. I had a mystery oil leak on my engine, turns out it was from the rear cylinder base gasket. Tightening the head nuts stopped it. Also, if yours is an early Series B with the original two part head stud arrangement be very careful as the hollow stud only goes part way into the crankcase- about one inch- and it's all too easy to strip the threads.
 

Albervin

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VOC Member
I was told that when re-torquing nuts or bolts you should unscrew them by 2 flats first. Does that still apply? Robert, it is never too late......
 
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