Topic: Honing Specs

[rhos1355]

Folks, I come cap in hand to ask you a few questions about barrel honing.
I'm in the planning stage of rebuilding my CB750 K2's engine and have been told that prior to reassembling the whole thing my barrels would need "just a tad" honing. I know about honing and it's advantages on helping lubricate a cylinder more efficiently as I used to help do it in my Dad's workshop in the 60's. But then most of our jobs were in the "wham-bang, thank you m'am" category. Now I wanna get it right.
I've decided to give the job to a local engineering firm, and whilst they are quite knowlegable, I want to know what to ask them to do. How much should they take off and what measurement is "just a tad" in the real world? And any other useful info would be most welcome.

Here are a few pics of the barrels as the stand now.

[WHALEMAN]

They will not "take off" any more than necessary to break the glaze and give a fine 30-60 degree hone. Are you using new rings? Honing has changed in the last 25 years and is now not as rough as it used to be. PM Mrieck and I am sure he can give you the number specs. I go with a finer hone, but it really depends on how you plan to break in the new rings. The act of seating rings is very complicated. With modern oils a faster break in is better. A finer hone requires a faster break in than a rough hone. This is all I think I know. Dan

[HondaMan]

You'll want to hone enough to remove that rust, but not so much that you install too much clearance. Stay in the .0005" to .0010" range, and try for a 60 degree crosshatch, if installing new rings.

If you're boring to the next oversize, (and it is the .25mm first oversize or more), you'll pick up a bunch of HP: on new bores like that, start with .0008" to .0012" clearance.

The general "new bore" figure is .0008" clearance with heavy honing: the "cleanup hone" must stay small, or too much piston slap and blowby will occur at high RPM.

[WHALEMAN]

http://www.enginebuildermag.com/Article/2450/cylinder_bore_surface_finishes.aspx

Pretty deep discussion on honing. Dan

[rhos1355]

Thanks folks, I'm learning already.

[WFO]

Honda man walked me through my honing it was real easy and cost about 8 bucks for the honer, it looks like a very young bore set so it should go pretty fast mine was about 1 minute per cylinder and clean your stones with kerosene don't like the crud build up.