Your Oil Shop - a division of Bishop's Performance
  Spark Plugs and Indexing Washers  
for Harley-Davidson® Motorcycles
*** Spark Plugs are priced individually ***
* Consult your owner's manual or service manual for proper part fitment, torque specs, and other important information.
 Twin Cam & Sportster * (12mm)
Harley-Davidson Spark Plug #32362-04 Harley-Davidson® 6R12   #32362-04 Your Price
$3.95 Each
 QTY
Champion Spark Plug Champion   #RA8HC $2.95 Each
 QTY
Autolite Spark Plug Autolite   #4164 $2.95 Each
 QTY
NGK Spark Plug NGK  Regular  #DCPR7E $3.50 Each
 QTY
NGK  Colder  #DCPR8E $3.50 Each
 QTY

 Evolution Big Twin & Shovelhead * (14mm)
Harley-Davidson Spark Plug #32342-04 Harley-Davidson®  5R6A   #32342-04 $3.95 Each
 QTY
Champion Spark Plug Champion   #RN12YC $2.95 Each
 QTY
Autolite Spark Plug Autolite  #4265 $2.95 Each
 QTY
NGK Spark Plug NGK   #BPR5ES-11 $2.95 Each
 QTY

Other Harley-Davidson/Buell Models  * (12mm)
Harley-Davidson Spark Plug #32335-04 Harley-Davidson® 10R12   #32335-04 $3.95 Each Sold Out


Spark Plug Indexing Washers

Spark Plug Indexing Washers 12mm,  Set of 8 = 2 each of 4 sizes
  fits most Twin Cam and Sportster
$9.00 /set
14mm,  Set of 8 = 2 each of 4 sizes
  fits most Evo and Shovelhead
$9.00 /set
Want to save the UPS shipping charges?
Are you ordering only index washers and don't need a tracking number?
Call Amy at (313) 537-5026 with your credit card information
and she will put them in an envelope and mail them to you for a total of $10/set.

Spark Plug Indexing

  One of the simplest ways to improve the combustion in your engine is to index the spark plugs. Indexing the plugs ensures that the gap is facing the combustion chamber. If the stem of the ground electrode is facing into the chamber, then the spark is shrouded from the majority of the fuel/air mixture (photo #4). When the stem of the ground electrode is facing away from the chamber, the fuel/air mixture will burn more quickly and completely (#2, #3). 
  The easiest way to accomplish this is to mark the insulator or metal base with a felt tip marker showing the location of the ground electrode stem.  Install the plugs and torque to 10 ft-lbs. Ideally, the gap will be facing toward the intake valve or centered between the intake and exhaust valves (#2, #3).  You want to be able to see your mark on the plug (#1). It's best to have the line fall between the two head bolts. If they are not within this range, try swapping the plugs from the front head to the rear head and vice versa, and they will usually come pretty close. We sell indexing washers in 4 thicknesses for both the 12mm and 14mm plugs, but they are rarely necessary. While some people may notice a difference in their engine’s performance, most will not.  As a general rule, we recommend replacing the spark plugs with new standard plugs every 5,000 miles.
Spark plug marked for indexing
Click photos below for a larger view - image will open in a new window.
spark plug properly indexed spark plug properly indexed - gap facing the intake valve spark plug properly indexed - gap is facing the intake valve spark plug improperly indexed - gap is facing away from the valves
#1 This is what you
see from the outside
#2 This is what it looks
like from the inside
#3 Correct
indexing
#4 Incorrect
indexing