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re: Oil burning and breaking in
- Subject: re: Oil burning and breaking in
- From: Ben Barkow <dr.ben@xxxxxxxxx>
- Date: Tue, 10 May 2005 11:08:18 -0400
Think crankcase breathing.
With a boxer, the crankcase volume is compact but the "tide" is
enormous (the same as the displacement, eh). With too much oil in
there, you might blow your seals.
That's really good... for me. My previous owner had a really big main
seal repair bill that he attributed to overfilling. And I had a very
favorable price for a bike with a new clutch the owner no longer loved.
My strong impression for pre-Oilhead engines is that it is very
important on the boxer engines to keep the oil level low. There is good
consensus that bringing it to the full level results in much burning.
Best (with the older engines) to keep at least a quarter-liter down,
The disfunctional character of the sometimes-pop-out oil level window
is really a PIA for an engine where oil level is esp. important (helps
cooling but can cause major destruction). And really puts you in a
pickel if you want to keep your level between say one quarter and one
half a liter down. If you think in terms of the volume of oil which can
be read from top to bottom it is quite small, esp. given the awkward
little filling hole (which won't hold my funnel up). Compare that to a
dipstick that can read over a liter and much more in the overfill
direction - sure will let you know if you overfilled.
The /2 had a fancy "gated breather" which is a rotating valve which
opens at certain times. That permits, as I poorly understand it, slight
positive pressure inside (perhaps to keep a little juice under the
rings) yet no resistance at all to breathing at other times. I suppose
you could combine a gated breather (no cheap feature) with modern PVC.
Ever hear the nutty idea of using abrasive cleaning powder as an
adjunct to the break-in process? My own opinion is that break-in
theories are largely silly magic, even those in owner's manuals. Sure,
breaking-in is a reality, but hard to believe that it makes any
difference too much how you do it so long as you follow general rules
about intelligent moderation in revs, lugging, etc. And one theory
contradicts another. One exception to silliness, in my belief-world, is
not to use synthetic oil for a while.
I'd also put ideas about when a bike is fully broken-in likewise into
the delusional category. Guys on the Airheads list have been talking
about 60,000 miles. Given all the variables, there just isn't any way
for a person to mount-up one morning and proclaim, "Yup, feels loose
and right today... guess it is finally broken in." For sure, different
features (such as rings) have their own curve of braking-in - which of
course signifies the start of breaking-down phase.
Ben Barkow, Toronto... 39 seasons on Beemers, 44 as a biker,
1961 R69s/rod, 1967-1999... really sup'ed up and fast
1984 R80RT/rod, 1998- 5 extra peak ponies in a wider flatter power band,
much modified 2-into-1 exhaust, CR 9.5, Keihin PJ 34mm oval carbs,
Uni filter, dual-rate springs with cartridge emulators, BT45/S11,
1999 R1100S, 2004- Leo Vince exh, JetHot coatings, Techlusion 1031,
K&N filter, 24 inch windscreen+Saeng edge)