Some Spark Plug Questions

 

Last time I got new plugs was my valve adjustment done by the dealership
about 2,500 miles ago.  2006 Honda Shadow 600, 27,000 miles.

Questions:

a)The shop manual says that for used plugs, they should be installed with 10
ft-lbs of torque (the procedure for new plugs calls for 1/2 turn after
hand-tight).  When I was doing other maintenance, I decided (for no good
reason) to be sure the plugs were torqued to at least 10 ft-lbs.  When I
tried all four plugs, one of them turned a little bit to get 10 ft-lbs, but
the other three did not turn.

I'm guessing the most likely explanation is that the dealership didn't
properly crush the washer on one of the new plugs when they installed it?

b)Do plugs ever work loose?  How or why?  If they do, what is the outcome?
Loss of compression?  Damage to the cylinder head due to the hot gases
leaking so that one has to do a helicoil repair?

c)After I torqued one of the plugs to 10 ft-lbs, I had trouble getting one
of the plug wires back on and had to remove it once then press it firmly a
few times to be sure it was fully seated.  I'm assuming that once the plugs
are in to 10 ft-lbs., monkeying with the plug wires by removing and
reattaching them won't work the plug loose?  Does monkeying with the plug
wires ever loosen the plugs?

Thanks for your patience.

Datesfat

 




They all do that sir (Dealers, not doing the job properly)

Vibration and because they've not been properly tightened.


They can rocket out of the hole with an almighty bang at worse, or simply
make a blowing noise as the gas escapes.


Not usually needed (helicoiling).


Not in my experience.


Better that than patient.

Btw, it never hurts to put a modicum of anti-seize compound on new plug
threads.

--
Beav

 

wrote:

I've only been riding 32 years; I haven't had the time nor the
expertise nor enough motorcycles to get to this level of detail wrt
spark plugs.

I'll defer to someone closer to your level of motorcycling immersion
to answer your questions.

 



That's Beav, that is :-))


--
BMW K1100LT  Ducati 750SS  Honda CB400F  Triumph Street Triple
Suzuki TS250ER GN250  Damn, back to six bikes!
Try Googling before asking a damn silly question.
chateau dot murray at idnet dot com

 

On Sat, 3 Jul 2010 20:42:52 -0400, "Datesfat Chicks"


Well the worst-case scenario might be the plug working its way loose,
the compression from the cylinder fires it out of the hole, driving it
like a rocket into the gas tank, just as the plug fires for the next
stroke, igniting the gasoline and lighting the motorcycle up in a
massive explosion.

See what happens when you think about shit too much!