Do you need to fully torque down when measuring bearing wear with Plastigauge?

[DayvW]

The reason I ask is that I remember reading somewhere where someone was concerned that repeated torquing and untorquing bolts reduces their life (so they didnt like to use Platigauge).  But I wondered whether you really need to torque them all the way to get an accurate measurement?

[DayvW]

Thanks .. I'll take a look.  On the pic below - I assume the 'A' on the shell marking indicates which of the various choice of shells I'd need?
So - you dont recommend actually measuring with Plastigauge then?

[Trigger]

As Oddjob said Davy. Forget about any markings on the shells. If you follow Oddjobs instructions there is no need for plastigauge.
Very well explained Oddjob  

[DayvW]

Ah .. now I see .. and attached are pics of the all that I think I need (and the crank markings are indeed still visible).  So it looks to me from what you say that the main bearings are therefore  A1 B1 B1 B1 B1 and the con rods A1 A1 A1 A1 ?  Thanks for the explanation - just what I needed!

[DayvW]

Thanks trigger6969 - sounds good to me. I havent taken the con rods off yet - but I'll do that to check they look good (and to ensure no crap in oil ways) - but the mains look good to me. 

[AshimotoK0]

Quote from: philward on March 02, 2014, 08:19:01 PM
I had the same problem but after checking under different lights, I saw the marks on the crank - really looked like a 2 year olds writing, almost a scribble! Having a real look might save you a some work with the plastiguage - took me ages to spot the marks on my crank
Phil


+1 those marks are hard to read and you need the right light level as there is very little contrast between the marks and the crank. They look like they were done with a wax crayon or lipstick!! obviously not, must be some kind of special marker pen the Japanese had.  I have convinced myself in the past that they had worn off but after a mug of tea and a re-examination they have always been there!

Link to Service bulletin #14 is useful (prices for the shells are a bit out of date though  ).

The diagram in the bulletin shows them as neat markings but the ones I have seen are hand done and the 'font' if you can call it that, is freehand.

 http://manuals.sohc4.net/CB750SB/750_14.pdf

Cheers..... AshD

[DayvW]

 I believe you Oddjob - honest  - perhaps the mileage is accurately low (around 23K it says on the mileometer) .. or the oil kind to that paint!

And - doh - yes ... I meant conrods A2s not A1s (typing - hopeless!).

Many thanks once again - much learned from you once again - this is - and will be for ages I expect - a terrific learning experience.

Now all I need to do is get her back together and running again .. how hard can it be ...  

[DayvW]

I will indeed take care when spannering (socketing!) those bolts - thanks for the head-up though.  All the main bearing shells are labelled top/bottom and 1-5 (bought myself 100s of little luggage labels for just this kind of job!)  -and yep on the conrods i did notice the manual was very clear at pojnting out the need to get the the right way round.  I shall progress - not so much slowly (though slowly it will be) but carefully (as I like to see it .  Who is it says 'measure twice, cut once' (carpenters, fabricators in general)?  Can apply that philosophy to sooo many things!