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Con Rod Identification
Posted: Mon Sep 23, 2013 8:48 pm
by fatpete
I was breaking down an old NC 30 engine I was given, it was an old race engine where the block cracked.
The con rods that have come out are different to any I have seen and I was wondering if anyone could ID them.
They have MLO . F(or R) 20 on the side and the con rod cap has MLO 2 on the end and no size or weight markings on the side.
They weigh about 7/8 g more each, then the other set I have.
If anyone knows anything about them I would be interested to know.
cheers
Pete
Re: Con Rod Identification
Posted: Mon Sep 23, 2013 10:58 pm
by VFRkieran
Have you measured how long they are? Possibility they are HRC rods if they arent standard but have the usual Honda part markings on them. Got any better photo's? Would like to see the pistons and cams if you have photo's of those too?
Re: Con Rod Identification
Posted: Tue Sep 24, 2013 5:31 am
by Neosophist
It's an NC30 engine right and not an NC24 engine?
Both NC30 and NC24 use ML0 (originally made for NC21/24) con-rods.
The rods were revisied in the nc24 from the earlier nc21 rods, perhaps lighter ive never compared the two, but perahps you have a set of earlier con-rods in there.
Re: Con Rod Identification
Posted: Tue Sep 24, 2013 6:45 am
by Cammo
The nc30 hrc conrods are 3 mm longer than the stock rods if that helps.
Re: Con Rod Identification
Posted: Tue Sep 24, 2013 7:40 am
by fatpete
They are the same length as standard and had standard pistons, I will try and take some better pictures later.
I take it that nc24 rods are interchangeable then.

Re: Con Rod Identification
Posted: Tue Sep 24, 2013 7:57 am
by Yakama
HRC rods also have NF2 stamped on them not ML0
Re: Con Rod Identification
Posted: Tue Sep 24, 2013 11:21 am
by Neosophist
fatpete wrote:They are the same length as standard and had standard pistons, I will try and take some better pictures later.
I take it that nc24 rods are interchangeable then.

Yes.. The NC30 uses the same rods as the later NC24s, hence the part number being ML0 and not MR8 (nc30 specific).
The rod design was changed once or twice during the NC21/NC24 production run, not sure what was changed as they all made the same power, so probably manufacturing costs or something were saved but there all interchangable.
Re: Con Rod Identification
Posted: Thu Mar 13, 2025 3:58 pm
by KarlosvB
Hi good reading about the conrods I guess that HRC stuff would. Put a hole in the wallet? Can any one. Let me know which way the. Markings face on the rods …… to the left or right of the engine facing from the engine rear I assume this is still a thing …. Well at least it was in my old xj650 and fz750 days I have figured out there r rearward nc21/nc24and forward facing rods oh any one have the specs on big end side clearance( for these) and oil clearance cheers
Re: Con Rod Identification
Posted: Thu Mar 13, 2025 11:50 pm
by magg
NC30 service manual in the library document section of this site may be of assistance.