Honda-SOHC

Other Stuff => Misc / Open => Topic started by: SteveW on March 16, 2023, 11:12:42 AM

Title: Re-torquing cylinder head bolts
Post by: SteveW on March 16, 2023, 11:12:42 AM
Rebuild the top end on my 1980 650 just before Christmas and it’s running perfectly with no leaks.

Should I re-torque the cylinder head bolts after a few miles or is there no need?
Title: Re: Re-torquing cylinder head bolts
Post by: Orcade-Ian on March 16, 2023, 01:46:36 PM
Hi Steve,
When I was serving my time in the Aircraft industry we occasionally had to re-torque various components but told never to just apply the torque wrench and go to the prescribed value because of the 'stiction' in the original fitting which can give an incorrect reading.  The process was to slacken one fixing and torque that to the correct setting, then move on to the next and so on.  With a head it would be necessary to follow the original sequence.  I certainly do it but whether the experts think it necessary - I'm sure they will chime in soon.

Ian

Obviously can't do it with stretch bolts but that doesn't apply to our machines.
Title: Re: Re-torquing cylinder head bolts
Post by: Oddjob on March 16, 2023, 03:55:19 PM
I would say it's not necessary Steve. First off you'd need to dismantle the top cover to get to the bolts, it's not leaking now but it may do if you disturb it, why take that chance. The other is when you get an engine done in the workshop they'll only do it once and then you take it away so it's not done in practice, I've never said to any owner of any engine I've done the head on "Bring it back in a few days so I can retorque the head" It goes out of the workshop and we forget about it.

Just leave it, if it's not leaking leave well enough alone is my advice.
Title: Re: Re-torquing cylinder head bolts
Post by: SteveW on March 16, 2023, 06:43:38 PM
Thanks guys, I’ll leave well alone then.
Title: Re: Re-torquing cylinder head bolts
Post by: Bryanj on March 16, 2023, 11:37:21 PM
Plus 1 to Ken, Honda dont say in any manual to retorque the head
Title: Re: Re-torquing cylinder head bolts
Post by: taysidedragon on March 17, 2023, 12:52:16 PM
I agree for these engines. It was different for the old Triumph/BSA engines. Common practice to do it with them, I guess because of different gasket materials - and more vibration! 😁
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