Topic: CB750 Main bearing replacement Question

[seebee750]

Thanks for the info. Food for thought indeed.
Could it be that one of the Yoshomira high flow pumps could be available on Ebay?
I am going to have a look at CB750 oil pumps myself, now that I have the theory down for the crank and rod bearings.
 Do you use an oil pressure gauge? What type would you recommend. After spending big money on parts I want to be sure of the oil pressure. What should the pressure range be?

 

[Clement2]

               I think because it has no stamped.

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Rapid Tooling

[rs_shadow0000]

All of this added approval in the crank wouldn't be a botheration IF new oil pumps (or hi-flo Yoshimura pumps) were still available, because the top end of the engine would not abjure for oil if a hi-flo pump could be plunked into place. But, as the basal end's clearances (and consistent leakages) increase, the top end gets beneath flow. Going to a added oil abject (20w-something instead of 10w-something) helps because the college bendability makes the beat pump move added oil breeze again. There is a point area even this advance is not abundant (mine is there, now), and the top end does not get abundant breeze at low engine speeds (mine: 2500 RPM on a 100 amount day will run it appealing dry), and the all-embracing burden drops a bit, too. All this signals the charge for new bearings.

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Stereolithography

[CG2000]

Seebee,

Good job and better persistence. Thanks for listening to those that know. You're one of us now  ;)You really have to see them the first time to understand. No stampings, no fancy letters. Just some Japanese guy knocking out measurements by the thousands on a daily basis and scribbling on some very hard metal. You have to read these in a "Japanese writing accent". They sure don't look like someone with native English writing skills did them, do they?!

 Crank = A-B ; A-B ; A-B ; A-B ; C-B 
 Rods  = 4-2 ; 4-3 ; 4-3 ; 4-3

Go to the chart and match up these combinations now. 4 greens and 1 brown for the crank. 

Here's the bit I don't understand. These codes only help you select the same shells that were originally installed at the factory. Since the crank must have worn somewhat since then the codes don't help select which shell thickness you should use NOW to ensure you hit the right oil clearance (0.03mm) for a measured diameter of crank pin or journal.

I think the missing information is what diameters (in mm) do the letters / numbers on the crank and or cases actually correspond to?

[bryanj]

Don't matter anyway as you can't be accurate enough with a micrometer, the factory used air gauges

[CG2000]

Regardless it would be helpful to know these diameters to work out the original shell thicknesses if, as in my case, there is no visible colors on the shells.


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[livetoride]

CG2000, the Owners Manual states the relevant shell colour based on the clearance you have on your crank / rod in a little, very hard to read for a layman, chart.