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Path: utzoo!watmath!clyde!cbatt!ihnp4!ihlpa!animal
From: animal@ihlpa.UUCP (D. Starr)
Newsgroups: net.cycle
Subject: Re: Flashing Oil Light
Message-ID: <1871@ihlpa.UUCP>
Date: Tue, 16-Sep-86 13:44:34 EDT
Article-I.D.: ihlpa.1871
Posted: Tue Sep 16 13:44:34 1986
Date-Received: Sat, 27-Sep-86 11:03:01 EDT
References: <1271@drutx.UUCP> <1848@ihlpa.UUCP> <20783@rochester.ARPA>
Organization: AT&T Bell Labs, Naperville, IL
Lines: 43

> In article <1848@ihlpa.UUCP>, animal@ihlpa.UUCP (D. Starr) writes:
> > ...  The only Japanese four-stroke engine I know of with an
> > oil-level light is the Yamaha V-twin, which is all roller bearings and
> > can't maintain more than two or three pounds of pressure.
> 
> I have a 1981 Yamaha 550 Seca.  It has also has an oil-level warning,
> rather than a oil-pressure warning.  It is a four-stroke in-line four
> with plain bearings.  I am actually rather glad to have the level
> warning, since it goes off sooner (before actual damage is likely to
> occur) in the usual case of running low in the sump.  I've had this
> happen twice after/during long distance trips and suffered no damage.
> 
> It's my impression that when an oil-pressure warning goes off, it's
> like the chip-detector in a helicopter:  You're already getting big
> time damage; land (pull over) the thing IMMEDIATELY.  Anyone care to
> comment on how long a bike engine lives after oil pressure fails?
> 
> Stu Friedberg  {seismo, allegra}!rochester!stuart  stuart@rochester

I have two stories to relate on running without oil; one of them is
from personal experience, the other is second-hand.

The second-hand story concerns a test supposedly performed by Harley
mechanics during the development of the Evolution engine.  Somebody
decided to find out how long this engine would run without oil, so they
got a test bike warmed up, drained the oil and took it out for a ride.
It went forty-some miles before showing any problems; then they stopped
the experiment and dismantled the engine for inspection.  They found
only minor piston seizure, which could be repaired with fine sandpaper.

Similarly, I ran the oil tank and lines on my Suzuki GT750 (two-stroke,
water cooled) totally dry somewhere in southwest Missouri one time, and
didn't notice until I had stopped for the night in Kansas City.  The only
symptom was trouble idling (possibly due to the above-mentioned minor
piston seizures); I refilled the oil tank, tossed some oil into the gas
to cover the line-priming time, and rode the bike another 25,000 miles
without engine problems.  As far as I can tell, I ran at least 150 miles
on the oil that clung to the bearings.

It's worth noting that all rotating shafts in *both* of the engines described
above are in roller bearings, which is probably why they survived.  Plain
bearings would probably not last more than a couple minutes without 
pressurized oil.