The agreeable points whether you ask the factory engineers or engine builders or savoy customers...
"The cylinder walls of a new engine are not mirror smooth as one might imagine. A special hone is
used to put a diamond like pattern of "scratches" over the entire area of the cylinder wall. The
cross hatch treatment of the cylinder walls plays an important role in proper break-in of piston
rings to cylinder walls. I mentioned that B.M.E.P. was necessary to the "break-in" process. Here is
how it works."
"If you cutaway a piston, ring and cylinder wall and inspect under magnification you see something
to the effect of "saw teeth"... Given that a film of lubricating oil holds the piston ring away
from the cylinder wall. Proper break-in of piston ring to cylinder wall requires that the ring rupture
or break through this oil film and make contact with the cylinder wall. During such "metal to metal"
contact, the little peaks on the ring face and cylinder wall become white hot and rub off. This
condition will continue to occur until the ring face and cylinder wall have established a smooth
compatible surface between each other. At this point, break-in is said to be relatively complete and
very little metal-to-metal contact will occur hereafter. In fact, as the break-in process
progresses, the degree of metal-to-metal contact will regress."
"There is one little "sticky wicky" in this process, that film of lubricating oil is there to prevent
metal-to-metal contact. That's exactly what it will do and really that's what we want it to do.
However, during the break-in process, we must have some minute metal-to-metal contact as
previously explained. Therefore, rupture of the oil film is necessary. The factors under the owners
control can retard this necessary rupture are low power and babying the engine..."
"During the normal break-in process the points or ridges of the honed-in scratches are partially
worn away. During the actual oil-film rupture, only the ridges on the piston rings and cylinder
walls contact each other. The little "valleys" between the ridges retain a film of oil and thereby
prevent a total dry condition between piston ring and cylinder wall. B.M.E.P. or combustion
pressure forces the ring against the cylinder wall. This is the "key" to the break-in process. You
can see then that low power (low B.M.E.P.) won't provide the same results and the break-in
process will require a longer period of time. However, time in this instance will have a detrimental
effect on your engine because any prolonged, low power break-in procedure usually leads to
"glazed" cylinder walls."
"During each power stroke, the cylinder walls are subjected to very high temperatures, often 4000
degrees F or higher. This period is very brief but nevertheless, long enough to cause oxidation of
minute quantities of some of the lubricating oil on the cylinder walls. Some of this oxidation will
settle into the "valleys" of the honed cylinder wall "scratches." Eventually this situation will fill
the "valleys" of the cylinder walls creating a smooth, flat surface. This is also a normal situation;
however the ring break-in process practically ceases when these valleys become filled or "glazed"
over."
"If this "glazed over process occurs before break-in is complete, in modern day language, "you
have had it." Excessive oil consumption resulting from incomplete ring seating will present itself
and the only certain remedy is rehoning the cylinder walls. This is both expensive and unnecessary."
My best advice is if you wish to know for *sure* the state of break in on your new bike then take a compression test... if the engine shows factory compression then ring seating is done... if you don't see factory compression then I advise more high revs to punch though the oil film...
