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Oil Leaks

To: land-speed@autox.team.net
Subject: Oil Leaks
From: ardunbill@webtv.net
Date: Thu, 29 Nov 2001 15:38:08 -0500 (EST)
Hi Folks, someone reprimanded me for giving you the idea that a Vincent
might leak oil.  The fact is that as manufactured, when well-maintained,
or expertly rebuilt, they didn't, and don't to this day.  Well, no more
than a microscopic seep here and there that might retain a few specs of
dust!

The bikes of the Old British Motorcycle Industry (I know nothing of
today's) did have some reputation for leaking.  The great designer of
the Vincent, P. E. Irving, once stated publicly, "Oil is devilish stuff
to control."  There is also the story of a young fella with a newish
Brit bike who went back to the factory Service Department to have a word
with the Manager about it.  After inspection, the Service Manager said,
"Son, I don't see what you're complaining about, do you take your bike
to bed with you?"

A late and dear friend of mine was a top engineer at BSA Motorcycles in
Birmingham, England in the early '50s.  We were chatting about the
well-known oil leak problems once and he said, "Bill, just look at the
usual bike aluminium crankcase.  It has all kinds of sections and widths
in it, with several lengths of studs holding it together.  Some parts of
it run much hotter than others, so there is diffential expansion here
and there.  The drive side main bearing area has a constant alternating
pull back and forth from the primary chain.  The cylinder studs are
pulling up on the top of it all the time, plus the constantly varying
combustion forces when it's running.  The case is split vertically and
has oil ponding inside over the split.  The one or two pistons are
pumping up and down all the time, creating a constantly varying air
pressure. The timing gear area has various stresses on it.  The whole
thing is vibrating.  Is it any wonder if it seeps a bit?"

When the Japanese came along, they did overcome a whole lot of the
trouble simply by making their crankcase split horizontal. 
The Old English bikes mostly were made to sell for a modest price, and
their quality was good, but in my opinion the only ones you could call
"aircraft quality" were the Vincent, and the production racers(to
include Works specials) built for long-distance roadracing by Norton,
AJS, Matchless, Veloce, etc.  When you design for long-distance racing,
you've got to be serious, and the said bikes generally cost twice one of
the company's bread-and-butter products.

BTW, I just ran across a good website for those who care for the
Vincent, thevincent.com.  This has an emphasis on the lore of the
company's Black Lightning and Grey Flash racers, and it appears to be
sponsored by some of the Los Angeles area Vin men.  Although I don't
agree with the accuracy of every statement that appears on it, they do
have a number of interesting items, and a Classified Section for those
who might be in the market.  Buyer Beware!!  Cheers from Ardun Bill

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