mm wrote:

On Fri, 17 Nov 2006 08:02:47 -0600, "HeyBub"
wrote:


mm wrote:

It seems to me that all the screws and bolts on my Japanese motorcycle
are metric, except the sparkplugs.

AFAICT, neither the threads nor the socket required for the sparkplugs
used in my Honda are metric. Is that so, and how did it happen?


Huh? I though ALL sparkplugs were metric - a residual from the days (~1900)


Well maybe the threads *are* all metric. I wanted to get a nut that
would go on a sparkplug, to make a spark tester, and none of the
English nuts fit. OTOH, I tried all the metric nuts and none of them
fit either. OT3H, they didn't have nuts in all possible metric sizes.
I think HD skipped from 12mm straight to 15mm, so maybe 14 would fit.


when the ONLY sparkplugs a U.S. engine maker could get came from Europe.


But even if the threads are metric, don't spark plug sockets come in
13/16 for the big ones, and other English sizes for the smaller ones?

Somewhere I have a set of metric sockets complete with extensions and
spark plug socket, and I've been looking for them ever since I got my
motorcycle. CAn't find them, so I don't know how the spark plug
socket is labeled. (I've been using a bunch of metric sockets
gathered from junk boxes along the way.)


Are you saying we are slowly converting Asia to the Imperial System?


Yes, that's why GWBush is in Viet Nam. He's promoting the inch, the
foot, the pound, and most of all, the caliber.



If you are inclined to email me
for some reason, remove NOPSAM :-)

The two most commonly encountered spark plug thread sizes a

M14 x 1.25

and

M18 x1.5

Someone with a lathe having metric screw thread capability could make
you a nut pretty easily.

Or maybe you could find a junk cylinder head and bandsaw out the plug
hole area?

*********** Trivia follows:

Some early US spark plugs used tapered pipe threads like this one I've
had kicking around for years:

http://home.comcast.net/~jwisnia18/temp/plug.jpg

It disassembled for cleaning and had dual outer electrodes and a knurled
nut for connecting the high voltage lead. A copper gasket sealed the
ceramic to the lower body.

Mine is in pretty rough shape, the insulator was cracked when I got it
and I epoxied it in place for show.

It is marked "Champion" on one side and "Maytag" on the other, so I
imagine it was used in the engine of one of those gas powered clothes
washing machines which were popular before rural electrification happened.

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.