Crank bearings/shells

[Mitchv60]

Evening chaps

My engine has been stripped and I've had the cases vapour blasted ready for a repaint.All the internals are in excellent condition but a couple of the crank shells are slightly marked.
To be honest they would be fine but as the motor is apart we will replace them as its a no brainer.
Is there some markings on the crank to say what size(colour)are required for replacements,the only marks we can seen anywhere is on the rear of the lower engine case and that is AAAA.

[Bryanj]

The crank etchings are very difficult to see but the genuine Honda manual points you at the correct place

[ginger_jim]

I have this advice after going through the same issues with a CB750 engine.  Send the crank to SEP in Kegworth.  Even if you fit the new shells you are still supposed to measure measure the gaps so any wear will mean extra tolerance.  SEP measure everything for you and supply new shells for around 200 quid (ex VAT).  Everything is returned packed and pre-lubed.  You will spend something in that region just to get the shells from DS.  At least this way you know everything will be 100% ready for rebuild!

[ginger_jim]

i should just add that the price is for the Big End and Mains.

[ginger_jim]

Hi Oddjob, I totally take your point.  Incidently I only had to send the crank and the letters from the crankcase.  SEP have all the measurements to work out the clearances.  I guess my problem was that I could not be 100% sure of the big end markings and this route provided me with a bit of peace of mind!  If I could have been sure of the code mapping there would have been no need as you say.

Regards, Jamie

[ginger_jim]

Yep the conrod marks weren't there.  I could read the marks of the crank lobe- they were all 4's but there was nothing on the conrods, that was after cleaning with petrol and using a Inspector Clouseau type magnifying glass :-)

We'll see what happens anyway.  Loads of spanner mates down here who swear by SEP.  Ill keep you updated !

[ginger_jim]

P.S Bryan had sent me the Honda service bulletin so I knew where to look!  Bryan also said the the marks are etched onto the conrod half but I could see bu££er all!

[matthewmosse]

Crank can be sent for £10 or so, you could probably send the cases too for that price. For my part I'd think it was woth the expence to know it's right.

[matthewmosse]

True, properly speaking I think plasitigauge or some such product should be clamped in the cases and the ammount of streach measured. This cannot be done without cases so the best they could achive is to measure the crank very accurately and supply according to that and rely on total accuracy and consistency in the manufacure of the cases. I know Honda are really good, but that really good every time? On the other hand it's streaching my skills for me to do that job - part of the reason I just swap engines if needed.

[Bryanj]

Perhaps I am cynical but i don't think there is a machine show in the UK that can measure to the accuracy of the original Honda air gauges

[ginger_jim]

Conjecture doesn't do anyone any good IMHO.  I was looking at paying ~ £200 for the shells from Dave Silver so im sorry chaps, but  as no-one has actually provided a solution as to how I would have measured the big ends with out a legible code on the rods i'm sticking to my guns.  SEP have done the same for others on the forum without any problems so we'll just have to wait and see. 

[ginger_jim]

OK - Mains are 10.74 each inc VAT = 107.40
Big ends                                         = 69.60

I gave SEP the case codes (BBBBB) so actually they are just going to sell me the shells that I would have got from Dave Silver but cheaper because they buy them in bulk.  My concern was the Big End measurement so it really depends which camp you sleep in - fit the biggest bearing or pay a very reasonable (in my opinion) price to get someone else to measure up. While I have a huge amount of respect for the collective knowledge on this forum, especially ex honda mechanics, lets be careful not to introduce too much anxiety for less experienced readers who may be unsure when faced with ambiguous decisions 

[Mitchv60]

I haven't gone any further with this as I made the decision to leave it until the cases had been painted so not to contaminate the clean metal.