Con Rods

[Bryanj]

Yes the rods could be different sizes but same weight from new and the cases will be stamped and wont changesize uless the shells sieze to crank and spin which would destroy the cases anyway

[4wDaz]

Did you find any markings on the shell edges ?
I had to do a bit of educated guesswork from the ones that were colour coded then try them in an unmarked conrod using Plastigauge to check the clearance.
My understanding is that you do not have to measure the crankcase as they are stamped with the codes.

No unfortunately, the crank had been removed from the engine by a previous owner years ago and the shells had been lost. Luckily the con rods were still attached but pistons had gone

[4wDaz]

So is it possible to get the bearing size without measuring the crankcase ? The cases are marked BBBAA
 
The main crank journals measurements are
No 1 – 31.986
No 2 -  31.986
No 3 – 31.987
No 4 – 31.988
N0 5 – 31.985

[Bryanj]

In the manual and the parts book is a cross reference table and in that you can convert the pin sizes to codes then use the table to get colour codes

[McCabe-Thiele (Ted)]

If you look at the tables in the parts manual you will see that they used different markers in the tables. Letter codes on one axis for mains shells, the same axis in big ends uses number codes.
I too found it confusing - over time it makes sense - also the table layout themselves are obvious I guess to an engineer it was difficult for me to see the symmetry in the columns if you get my meaning.

[4wDaz]

Thanks i'll have a look when i get home from work and see if i can work it out. Im no engineer and moneys tight so I cant afford to order the wrong bearings, I'm sure i'll get the hang of it in the end

[McCabe-Thiele (Ted)]

I've sent you a PM. Ted

[McCabe-Thiele (Ted)]

I would suggest remeasuring as the smallest size listed by Honda for the crank journals is 32.000.

The tables show 32.0 down to 32.000 - 0.030 so that is down to 31.970 so what is wrong with his readings they look plausible to me or am I missing something here?

[4wDaz]

I would suggest remeasuring as the smallest size listed by Honda for the crank journals is 32.000.

Ive checked them a dozen times

[4wDaz]

[4wDaz]

Trouble is you need a REALLY good micrometer to measure them accurately. By good I mean professional engineers workshop good. Probably costing hundreds if not into the thousands I'd imagine.

I have a new mitutoyo digital micrometer that i used but ill get it checked tomorow at the engineers whos doing my rebore

[4wDaz]

Where's that from Daz, my info came out of the official Honda parts book.

Well that's interesting, the workshop manual and the parts book show the same figures but in a completely different way. Seems Ted was right, I presumed it was a misprint as I've not seen Honda do that before, they tend to go up in sizes on the charts not down, so 1 would be 32.000 to 31.99 (who the hell writes figures like that) 2 would be 31.99 to 31.98 and 3 would be 31.98 to 31.97. Very odd and not something I've ever noticed before, the 500/550 shell bearing selection is far easier to understand.

I also have a Mitutoyo digital gauge and whilst it's good I don't think it's that good.

Its out of the 400 workshop manual in the Aladins cave download section http://info.sohc.co.uk/download/cb350f-cb400f-shop-manual/

[4wDaz]

If your figures are correct BTW, you'd need Brown, Brown, Brown, Green, Green. As all your figures are within the middle column and are thus No2.

Thanks for that, Ted came up with the same colours so I'm happy to go with that. Just need some overtime in now to pay for them