Re: [ST] New engine break-in

["colt4530@xxxxxxxxxxx" <colt4530@xxxxxxxxxxx>]

I at least partially disagree with Mototunes, too.  The highest stress
region of most engines is the cam lobes.  Too much RPM too quickly will
ruin them.  In addition, Main and rod bearings are *supposed* to run on an
oil film, but don't quite when new.  There is little logical basis to
believe there is any "heat cycling" going on in most engines, especially
water-cooled ones.  An air-cooled 2-stroke dirt bike is perhaps another
matter as the bridge in the exhaust port MAY expand into the bore with heat
and could be gently worn away with repeated short running periods.  That
is, of course, not quite heat cycling.

As a kid, I used to do something like Mototunes recommends to my air-cooled
Honda singles, with disasterous results like oil-burning in 4000 miles and
piston seizures.

John

Original Message:
- -----------------
From: David W. Funk dwf@xxxxxxxxx
Date: Wed, 11 Dec 2002 13:48:37 -0800
To: ST@xxxxxxxxxxxxxx
Subject: Re: [ST] New engine break-in


I disagree with the mototuneusa guy!
There is more to breaking in a new engine then seating the rings. Just
think 
of all the moving parts, bearings, and sliding surfaces. All wearing parts 
should be given a change to "break in". Heat cycling is real and has
nothing 
to do with heat treating anything. Hot parts expand, cold contract. The
mini 
high spots that are being "broken in" cause local hot spots, so it is best
if you 
let things cool down from time to time during break in.
.

David W. Funk
'00 Triumph Sprint ST
Pleasanton, CA

On Wed, 11 Dec 2002 07:55:54 -0800, Rick & Joyce wrote:

>There have been many examples of excessive oil consumption on
>engines where the factory running-in limits have been strictly
>observed.  If you want the rings to seat properly, suggest you
>read http://www.mototuneusa.com/break_in_secrets.htm
>for some insight as to why you should be visiting redline right
>away!


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