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Main Bearing identification

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Bitsa (Ralph Wright - RIP):
Hi Guys.
A while ago when I could not match the crankcases with the crank, the etching on the crank was not visable I thought what the hell and rang Haynes.They were very nice and put me through to a Honda racing mechanic who told me after 30 or 40 years or so just buy the biggest shell fit them and re run it in gently.I have to say it shook me a bit and did just that.Fitted them the crank span after torquing down and so far touch wood no problems.As always leave it to you, in the past had good advice but also some shit advice.
Cheers
Bitsa

philward:
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

Trigger:
Bitsa is right on this one. Between the smallest which off the top of my head is Yellow, to the largest which is Black. The difference is 0.0015 off the top of my head. I always use black but, do apply some running-in compound.  And as Bitsa says: Take it slowly.

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

--- End quote ---


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Link to Service bulletin #14 is useful (prices for the shells are a bit out of date though  ;D).

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

Cheers..... AshD

Trigger:
60p a shell, trade price. The ones i got last week were coming up near a tenner.

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