Topic: Mystery Oil Control Dowel

[Scars Motor Co]

Hello! (my first post )

I'm rebuilding a 1979 CB 650z, I took off the sump to discard the remains of a cracked piston sleeve. Whilst doing so I found a strange object that I couldn't relate to the piston sleeve breaking up. I'm pretty sure it's an oil control dowel, it's now crushed up so can't be 100%. Anyhow any idea where that would have come from? I've got the two oil dowels that sit in the cylinder block, but in any case it would be impossible for one to find it's way into the sump.

Any thoughts on this? My only thought at the moment is that the engine has been taken apart before and it's been dropped into the engine by someone else and not retrieved?

Thanks!

[DaveBarbier]

Would need to post a picture. You can upload to a site like imgur.com and then post the link because for your first post you may not have permission to post pictures.


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[DaveBarbier]

That being said, I don't know of any "oil control dowel". Only thing I can think of are the two oil jets located in between the top case and the cylinders. But no way they can work their way down into the oil sump. A picture is required.


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[Scars Motor Co]

Ok thanks for getting back to me. Please see attached photo of the object...

[Scars Motor Co]

...Oil control dowel is what they call it in my manual but yep also could oil jet

[Scars Motor Co]

Another pic...

[DaveBarbier]

...Oil control dowel is what they call it in my manual but yep also could oil jet

Is what they call what? This part or the dowel between the case and cylinders?

Looks to me like a broken oiler for the primary chain. Part number 10 in the fiche. If it is, the primary chain would have to be pretty loose for it to shear it off. Maybe check the tensioner and chain slack.

https://www.cmsnl.com/honda-cb650sc-nighthawk-1982-c-usa_model475/partslist/E++15.html#results

You may be able to drop the pan and stick your fingers around there to try to feel it.

You can see it in my picture.

[Scars Motor Co]

Ok thanks for the info. I've split the crankcase so I can get into it. Which part are you referring to in the picture?...Is it what I have circled in red?..

[DaveBarbier]

Yes, that's what I was thinking.


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[Scars Motor Co]

Ok cool, I'm not i the garage till Thursday so I'll check to see if it's still intact or if it has been shredded by the primary chain. Thanks!

[Scars Motor Co]

It's not the oiler for the primary chain so still a mystery

[Jerry Rxman Griffin aka MuthaF'er]

Contact/pm CB650 (Terry)

[enwri]

The only other thing about that size and shape is the Cap, Start Roller Cb650sc Nighthawk 1982 (c) Usa on the same parts page as above, can they get out?

[DaveBarbier]

As you mentioned earlier, Scars, it may be something totally unrelated to the bike. I can't think of anything else it may be, but I'll keep thinking. What's the state of the motor? Torn down and you're doing a full rebuild?


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[The Lone Builder]

Funny what you find in there.

Having replaced the inner bearing on my mainshaft, I replaced it in the case. There "attached" to the end was a small piece of ragged metal. It had the number/letters 1TN on one side which was smooth, the other being rough.

Years ago (before my time) the bike had suffered  a broken chain that trashed the case. I wondered if the bit could have been from a bearing race - at first I thought it said NTN.

Could it have resided inside the mainshaft all these years and only been knocked free as I drove the bearing onto the other end?

Unfortunately, I left it on the shelf too long before taking a photo and it got cleaned up!!