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Discussion Starter · #1 ·
I am about to install new rings in my 1992 GSXR600. I have new OEM rings in a package from Suzuki. I know you shouldn't hone the cylinder walls if you have cast iron rings, but you are supposed to for chrome moly rings. Anyone know if the stock rings are cast iron? They have a dull dark grey appearance which looks like cast iron but it could just be a coating. I would expect chrome moly to be shiny as well, but that may not be true. Thanks.
 

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sickboy
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I know you shouldn't hone the cylinder walls if you have cast iron rings.
Not sure who told you that but that is most def not true. It is best to hone them in a two step process first with a 220 grit then a 400.

If they are moly faced rings then you usually start with a 280 then a 400 stone or a 600 diamond hone. This is most important because if you finish hone with a grit under 320 the coarsness of the walls will chip the moly facing and destroy the rings and possibly the cylinder walls.
 

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sickboy
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Article from Engine Builder Mag...

"For plain cast iron or chrome rings in a stock, street performance or dirt track motor, hone with #220 grit silicon carbide stones (or #280 to #400 diamond stones) to within .0005″ of final size. Then finish the bores with a few strokes using an abrasive nylon bristle plateau honing tool, cork stones or a flexible abrasive brush.

For moly faced rings in a street performance, drag or circle track motor, hone with a conventional #280 grit silicon carbide vitrified abrasive, then finish by briefly honing to final size with a #400 grit vitrified stone or #600 grit diamond stone (or higher), plateau honing tool, cork stones or a brush.

For stock and street performance engines with moly rings, an average surface finish of 15 to 20 Ra is typically recommended. For higher classes of racing, you can go a little smoother, provided you don’t glaze the cylinders.

For moly or nitrided rings in a performance motor, hone with #320 or #400 vitrified stones, and finish with #600 stones, cork stones, a plateau honing tool or brush."
 

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Discussion Starter · #4 ·
Well, I've been doing a lot of reading on it lately. I guess it seems like it's more of an opinion that cast iron rings can seat in work-polished bores. There was supposedly a study by the SAE about not rehoning for cylinder ring replacement but I can't find it since they want money in exchange for their articles. I read quite a few aircraft mechanics don't rehone if they are just replacing piston rings with cast iron ones.

It seems that honing and the subsequent break-in removes more material from the cylinder walls vs not honing:
"in the early stages of
breaking-in, the surfaces are smoothed mainly by the removal of material
from the tops of asperities. However, the asperities were originally of a 0.48
um center-line average height whereas an average of 2.1 um of material was
worn away before the flat tops were seen. This suggests that the action of
the piston rings is to develop new asperities well below the level of the hone
marks. "
however honing creates a hydrodynamic bearing surface that reduces mechanical losses at the expense of increasing exhaust emissions.

Why I was considering not honing was because the bores eventually polish anyway, which negates any advantage of the honing marks. So I will potentially have higher mechanical losses but decreased blowby / oil consumption.

I've read a bunch on it, but here are a few of the better articles I found. I'm probably way overthinking this, but I can't help it. It's just a flaw in my personality and probably what makes me a good engineer.
http://deepblue.lib.umich.edu/bitstream/handle/2027.42/26638/0000180.pdf?sequence=1
http://link.springer.com/article/10.1007/s11249-010-9733-y
http://generalaviationnews.com/2012/06/03/the-marriage-between-piston-rings-and-cylinder-wall/
http://www.snowvalley.20m.com/bikes/dnthone.htm
 

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Hard Core Sledder
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The hone is what wears the rings into the bore. .... ring "seating" is done in the first couple hrs of life. So its imperative that you break in an engine properly.... varied throttle position and short burts of HIGH load staedily increasing duration of load. Oil change at 50 miles and let the muffugger eat... you will hqve better ing seal . More compression and less blowby contaminating your oil .

Flame on.
 

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Discussion Starter · #6 ·
Thanks guys. I've done some more reading and still don't really understand exactly what the rings are doing when they "seat", but I ran across a couple forum posts from guys that didn't hone a cylinder and had excessive oil consumption until they tore the engine down and honed it.
 

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Hard Core Sledder
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Heres some good reading for you please read the following in the order posted... the last link will be to all his articles...i encourage everyone to read them ..

http://www.mototuneusa.com/break_in_secrets.htm

Pt2.
http://www.mototuneusa.com/power_news_--_future_horsepower.htm

Pt3.
http://www.mototuneusa.com/power_news_--_the_factory_superbike.htm

Pt4.
http://www.mototuneusa.com/power_news_--_the_need_for_speed.htm

Pt5.
http://www.mototuneusa.com/power_news_--_circular_logic.htm


Link to all articles... theres a bit of philosophy in the reading too..

http://www.mototuneusa.com/thanx.htm
 
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