Crankshaft bearing selection bulletins/ADVICE NEEDED

[AshimotoK0]

Trying to sort out new bearing shells for my 750K0 and dug out the old Honda Service Bulletins... I have probably put these on before but for anyone who has not seen them before,  here they are.

Ash

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[AshimotoK0]

I think the diagram on page 4 of the first bulletin asnd similarly on page 2  of the second bulletin is wrong though because on the ones I have seen the weight code and journal size codes are each on opposite sides of the con-rod

[AshimotoK0]

Looking at my crankshaft main bearing measurement 1 journal is coming out a green and the other 4 yellow but I have enough green shells NOS for the 5 journals. Will I get away with all greens if I take it carefully on first running the engine? Suppose this is one for Bryan, Oddjob and Trigger and other old sages  . I don't want to take the shells out of the sealed Honda  bags and Plasitigage them on the crank unless I am  fairly sure.

Ash

[Bryanj]

Ash, I was told that Honda built them as if they had clearances found after a running in period so that all they needed was bedding in so even if you fitted all black and simply run it in with extra oil and filter changes I am 99.9% sure you will be OK. The engine in No 36 was built with all black and was OK all the time till it got burnt---would still love some time with the culprit and a megger

[AshimotoK0]

Ash, I was told that Honda built them as if they had clearances found after a running in period so that all they needed was bedding in so even if you fitted all black and simply run it in with extra oil and filter changes I am 99.9% sure you will be OK. The engine in No 36 was built with all black and was OK all the time till it got burnt---would still love some time with the culprit and a megger

How about all greens then Bryan,  for mains instead of yellow, as described? I am using the crank & rods  you sold me yonks ago  from your infamous lock-up BTW  It measured up pretty nice.

Ash

[AshimotoK0]

I was told it would be OK to use the colour either up or down a size without any detriment, as green is next to yellow in the sizing chart that should be ok Ash, just run it in nice and easy.

Funny how Honda told everyone to ignore these "Production marks" in the workshop manuals but then issued bulletins like these which made a mockery of that statement.

Cheers mate .. I suppose greens will be slightly tighter so should bed in nice. What do you apply to bearing surface when you Plastigage and during assembly? Big ends next .. all my 13  big end shells NOS are yellow but I reckon I need 3 sets of yellow and one green. So at worst will only have to buy two shells and at least the big end ones are slightly cheaper. What's the cheapest place?

Also I have three NOS, but not bagged,  big end shells that look like they are  marked green on the side (lime green)  but when I compare them with a bagged NOS and previously sealed one, with Honda label 13218-300-013 in the packet, they too have the same colour paint (well more like lacquer)  but they are supposed to be coded yellow (described as 'bearing D'). Any idea how green the green should be cw yellow?

Ash

[Bryanj]

Glad that crank was OK mate, bugger to post tho' I am certain you will be OK with what you suggested just when built remember higher revs are better than "Lugging" the engine and change oil every 500 for 3 times

[Bryanj]

I will be contraversial and say that if i am building an engine that is to sit for a while before use i have always used coppaslip (original version) turns the oil  FUNNY COLOUR BUT NEVER HAD ANY PROBLEMS ON ALL THE hONDA AND eSSEX v6 THAT I BUILT

[Bryanj]

Got from my Uncle who ran a real garage way back when, didn't mean to shout its this damn dyslexic keyboard that does wierd things when the batteries get low

[AshimotoK0]

So do I Plastigage or not given that I am pretty sure my measurements were spot on as the guy that measured them is an old engineering 'sage'  from the NEL ? 

Must admit that the old SOHC four crank (a 400/4) I ever fitted new shells to, I didn't Plastigage and it was fine (the 400/4 crank and shells on my current 400/4 looked so nice I just left well alone and refitted). 

Having said this the Honda shop manual specifically tells you to Plastigage and not to rely on measurements.

Ash

[Trigger]

Ash, I was told that Honda built them as if they had clearances found after a running in period so that all they needed was bedding in so even if you fitted all black and simply run it in with extra oil and filter changes I am 99.9% sure you will be OK. The engine in No 36 was built with all black and was OK all the time till it got burnt---would still love some time with the culprit and a megger

How about all greens then Bryan,  for mains instead of yellow, as described? I am using the crank & rods  you sold me yonks ago  from your infamous lock-up BTW  It measured up pretty nice.

Ash

Ash I used to build CX500 engines with all Green shells. You will have more clearance once the engine is run in. Use Graphogen running in compound to match the shell to the crank and it comes out after the first 500 miles oil change. Black shells just need to be run in a bit more.

[Bryanj]

Ash, I think you are overstressing mate. Consider the facts

(1) its an old motorcycle no matter how many new bits

(2) You are unlikely to rag the arse off it in any way that comes close to its original owner(s)

(3) Being honest its probably going to be a sunny high day and holiday bike

(4) No matter what you build it with, run it in nicely(but not too carefully) with lots of oil changes and it will outlast either of us!!

[AshimotoK0]

Ash, I think you are overstressing mate. Consider the facts

(1) its an old motorcycle no matter how many new bits

(2) You are unlikely to rag the arse off it in any way that comes close to its original owner(s)

(3) Being honest its probably going to be a sunny high day and holiday bike

(4) No matter what you build it with, run it in nicely(but not too carefully) with lots of oil changes and it will outlast either of us!!

Point taken 

[Trigger]

All built with green

[Chris-freckle]

Hi Ash you have probably sorted this now but here's my bit , use the correct bearings as specified by Honda, why spend a fortune restoring / rebuilding your motor using the wrong bits, also use molybdenum disulfide grease when assembling plain bearings.