Honda-SOHC

SOHC.co.uk Forums => CB750 => Topic started by: maxhammond on December 30, 2018, 04:54:18 PM

Title: Torque settings
Post by: maxhammond on December 30, 2018, 04:54:18 PM
Just reassembling the  front end.
Does anybody know what the torque settings are for the fork leg pinch bolts top and bottom.
1974 K4
Title: Re: Torque settings
Post by: Paulreade on December 30, 2018, 05:04:30 PM
Does this help
Title: Re: Torque settings
Post by: Nurse Julie on December 30, 2018, 05:45:01 PM
I think as the name suggests it is just pinched up, so no torque setting. Someone will correct me if I'm wrong, I'm sure 😀😁😁
Title: Re: Torque settings
Post by: Andrew-S on December 30, 2018, 06:47:17 PM
Do the above torque values apply across the CB750 range, K1 in particular?

Cheers
Title: Re: Torque settings
Post by: Trigger on December 30, 2018, 07:22:23 PM
If you do the sump bolt to 32.5, you will be looking for a new sump pan  :o And 86 on the flywheel bolt  >:(
Title: Re: Torque settings
Post by: Green1 on December 31, 2018, 01:43:04 PM
Never owned a Torque wrench I just do everything to the setting of that feels about right.

Saying that if I had to dig into the engine a little deeper I still wouldn't get one I would get Graham to do it.  ;D
Title: Re: Torque settings
Post by: Rob62 on December 31, 2018, 02:07:48 PM
I’d go with Honda’s chart but would always target the lower value for the sake of mechanical sympathy..... they know, they designed and built them.
Title: Re: Torque settings
Post by: Nurse Julie on December 31, 2018, 02:32:32 PM
I was taught by him indoors to always go for the lower values too. Those settings were applicable for when the fixings were brand new, and the metal the fixing is going in to was brand new but maybe 40-50 years old now. Also, as with all Honda translated documents, there are some errors in the values printed.
Title: Re: Torque settings
Post by: K2-K6 on December 31, 2018, 02:34:37 PM
If you do the sump bolt to 32.5, you will be looking for a new sump pan  :o And 86 on the flywheel bolt  >:(

That is weirdly high for the sump bolt isn't it.  Don't think I'd get anywhere near that.

Something in those numbers as well ( for sump drain bolt)  the range from bottom number to top number increases, by getting close to,  50% over and above the lower number.  That just can't be right.

Someone recently asked me if I could account for the range of torque settings specifically quoted for the 750 engine, for which I couldn't come up with a competent answer.

I've studied (decent time ago)  how torque stretches studs, compresses thread pitch in nuts etc,  looked at elongation of tensioned studs, stretched materials through yeald point and so on,  but just can't see why they quote such a wide range rather than give a target.

If you add the range together with a error percentage for torque measuring device,  it could be miles apart from the reality.
Title: Re: Torque settings
Post by: Rob62 on December 31, 2018, 09:12:23 PM
Torque isn’t so critical on these machines, so long as the figure is high enough to hold it together and not too high to cause damage...that’s probably why there is a fairly wide target to hit.... like a few have already said, you can get by without a torque wrench on most jobs...in fact probably everything except the crank cases and cyl head....
Title: Re: Torque settings
Post by: Nurse Julie on December 31, 2018, 09:24:46 PM
Torque isn’t so critical on these machines, so long as the figure is high enough to hold it together and not too high to cause damage...that’s probably why there is a fairly wide target to hit.... like a few have already said, you can get by without a torque wrench on most jobs...in fact probably everything except the crank cases and cyl head....
As engine builders that probably why we have so many torque wrenches around then 😀😀😀😀😀 I do see Trig using them quite a bit when restoring whole bikes as well though.
Title: Re: Torque settings
Post by: Rob62 on December 31, 2018, 09:51:22 PM
Absolutely 😄 i use mine too although its a bit past its sell-by-date to be honest, i could do with a new one...... im not suggesting you should do without. A friend of mine regularly breaks his bikes by overtightening stuff...I’ve even watched him crack indicator lenses by overdoing it with his screwdriver. But you can usually manage without if necessary.. as long as you’re not ham-fisted 💪
Title: Re: Torque settings
Post by: Trigger on January 01, 2019, 09:31:10 AM
If you do the sump bolt to 32.5, you will be looking for a new sump pan  :o And 86 on the flywheel bolt  >:(

That is weirdly high for the sump bolt isn't it.  Don't think I'd get anywhere near that.

Something in those numbers as well ( for sump drain bolt)  the range from bottom number to top number increases, by getting close to,  50% over and above the lower number.  That just can't be right.

Someone recently asked me if I could account for the range of torque settings specifically quoted for the 750 engine, for which I couldn't come up with a competent answer.

I've studied (decent time ago)  how torque stretches studs, compresses thread pitch in nuts etc,  looked at elongation of tensioned studs, stretched materials through yeald point and so on,  but just can't see why they quote such a wide range rather than give a target.

If you add the range together with a error percentage for torque measuring device,  it could be miles apart from the reality.

Torque settings is a minefield when it comes to old threads  ;)
Title: Re: Torque settings
Post by: Spitfire on January 01, 2019, 11:20:11 AM
I must admit that when I was regularly working on bikes I was used to working without a torque wrench apart from the obvious cylinder head type jobs, but nowadays it's rare for me to do any serious work on a bike so I do have a selection of wrenches which I use all the time.

Cheers

Dennis
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