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Harley Davidson Spark Plug Cross Reference

harley spark plug fitment - Harley Davidson Spark Plug Cross Reference

Intro

Table of Contents

Harley Davidson Spark Plug Fitment Chart

ManufacturerModelStandard PlugIridium PlugElectrode Gap
HARLEY-DAVIDSONBREAKOUTNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONBREAKOUT (EURO 4)NGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONBREAKOUT PRO STREET   
HARLEY-DAVIDSONCVO ROAD GLIDE CUSTOM   
HARLEY-DAVIDSONCVO SOFTAIL CONVERTIBLENGK DCPR8ENGK DCPR8EIX 
HARLEY-DAVIDSONCVO SOFTAIL DELUXENGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONCVO STREET GLIDENGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONCVO STREET GLIDE (114 CUI)NGK CR9EIX 0.8-0.9 MM
HARLEY-DAVIDSONCVO STREET GLIDE (117 CUI)   
HARLEY-DAVIDSONDUO GLIDE (PANHEAD)NGK R5670-5  
HARLEY-DAVIDSONDYNA FAT BOBNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONDYNA FAT BOBNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONDYNA FAT BOBNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONDYNA FAT BOB (EURO 4)NGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONDYNA GLIDE CONVERTIBLENGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONDYNA GLIDE LOW RIDERNGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONDYNA GLIDE LOW RIDERNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONDYNA GLIDE LOW RIDER (EVOLUTION)NGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONDYNA GLIDE LOW RIDER (TWIN CAM)NGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONDYNA LOW RIDERNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONDYNA LOW RIDER (EURO 4)NGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONDYNA LOW RIDER SNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONDYNA STREET BOBNGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONDYNA STREET BOBNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONDYNA STREET BOBNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONDYNA STREET BOB (EURO 4)NGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONDYNA SUPER GLIDENGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONDYNA SUPER GLIDENGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONDYNA SUPER GLIDE CUSTOMNGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONDYNA SUPER GLIDE CUSTOMNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONDYNA SUPER GLIDE CUSTOMNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONDYNA SUPER GLIDE SPORTNGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONDYNA SUPER GLIDE T-SPORTNGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONDYNA SWITCHBACKNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONDYNA SWITCHBACKNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONDYNA WIDE GLIDENGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONDYNA WIDE GLIDENGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONDYNA WIDE GLIDENGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONDYNA WIDE GLIDE (EURO 4)NGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONDYNA WIDE GLIDE (EVOLUTION)NGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONDYNA WIDE GLIDE (TWIN CAM)NGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONE / EL KNUCKLEHEAD (61 CUI / OHV)   
HARLEY-DAVIDSONELECTRA GLIDE ULTRA CLASSICNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONELECTRA-GLIDE 1200 (SHOVELHEAD)-74: NGK XR575-: NGK BPR5ES-11-74:0.7 / 75-:1.1 MM
HARLEY-DAVIDSONELECTRA-GLIDE 1340 (SHOVELHEAD)NGK BPR5ES-11NGK BPR5EIX-111.0 MM
HARLEY-DAVIDSONELECTRA-GLIDE CLASSICNGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONELECTRA-GLIDE CLASSIC   
HARLEY-DAVIDSONELECTRA-GLIDE STANDARDNGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONELECTRA-GLIDE STANDARDNGK DCR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONELECTRA-GLIDE STANDARDNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONELECTRA-GLIDE ULTRA CLASSICNGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONELECTRA-GLIDE ULTRA CLASSICNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONELECTRA-GLIDE ULTRA CLASSIC   
HARLEY-DAVIDSONELECTRA-GLIDE ULTRA CLASSIC (TWIN CAM)NGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONELECTRA-GLIDE ULTRA LIwithED / LOW   
HARLEY-DAVIDSONELECTRA-GLIDE ULTRA LIwithED / LOWNGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONFAT BOY (EVOLUTION)NGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONFAT BOY (TWIN CAM)NGK DCPR7ENGK DCPR7EIX1.0 MM
HARLEY-DAVIDSONFAT BOY INJECTION (TWIN CAM)NGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONFAT BOY SNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONFAT BOY / FAT BOY SPECIAL (FLSTFB)NGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONFAT BOY / FAT BOY SPECIAL (FLSTFB)NGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONFAT BOY / FAT BOY SPECIAL (FLSTFB)NGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONFORTY-EIGHTNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONFORTY-EIGHTNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONFORTY-EIGHT (EURO 4)NGK DCPR7ENGK DCPR7EIX1.0 MM
HARLEY-DAVIDSONFREEWHEELER (EURO 4)NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONFX 1200 SUPER GLIDE / FAT BOBNGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONFX 1340 SUPER GLIDE / WIDE GLIDENGK BPR5ES-11NGK BPR5EIX-111.0 MM
HARLEY-DAVIDSONFXR SUPER GLIDENGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONHERITAGE SOFTAIL CLASSICNGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONHERITAGE SOFTAIL CLASSICNGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONHERITAGE SOFTAIL CLASSICNGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONHERITAGE SOFTAIL CLASSICNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONHERITAGE SOFTAIL CLASSICNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONHERITAGE SOFTAIL CLASSIC (EURO 4)   
HARLEY-DAVIDSONHERITAGE SOFTAIL SPECIAL / NOSTALGIANGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONHERITAGE SPRINGERNGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONHYDRA GLIDE (PANHEAD)NGK R5670-5  
HARLEY-DAVIDSONLIVEWIRE   
HARLEY-DAVIDSONNIGHT RODNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONNIGHT ROD SPECIALNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONNIGHT ROD SPECIALNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONNIGHT ROD SPECIAL / ABSNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONROAD GLIDE (107 CUI)NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONROAD GLIDE SPECIALNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONROAD GLIDE SPECIAL (EURO 4)NGK CR9ENGK CR9EIX0.8 – 0.9 MM
HARLEY-DAVIDSONROAD GLIDE ULTRANGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONROAD GLIDE ULTRA (EURO 4)CHAMPION P-RG6HCC  
HARLEY-DAVIDSONROAD KINGNGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONROAD KINGNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONROAD KING (EURO 4)NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONROAD KING (TWIN CAM)NGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONROAD KING CLASSICNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONROAD KING CLASSICNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONROAD KING CLASSICNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONROAD KING CLASSIC (EURO 4)   
HARLEY-DAVIDSONROAD KING CLASSIC (TWIN CAM)NGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONROAD KING CUSTOMNGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONROAD KING CUSTOMNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONROAD KING SPECIAL (EURO 4)NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONROCKERNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONROCKER CNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONSEVENTY-TWONGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONSOFTAIL BAD BOYNGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONSOFTAIL BLACKLINENGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONSOFTAIL BREAKOUT (107 CUI)NGK CR9EIX  
HARLEY-DAVIDSONSOFTAIL BREAKOUT (114 CUI)NGK CR9EIX  
HARLEY-DAVIDSONSOFTAIL CROSS BONESNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONSOFTAIL CUSTOMNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONSOFTAIL CUSTOM (EVOLUTION)NGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONSOFTAIL DELUXENGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONSOFTAIL DELUXENGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONSOFTAIL DELUXENGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONSOFTAIL DELUXENGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONSOFTAIL DELUXE (107 CUI)NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONSOFTAIL DEUCENGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONSOFTAIL FAT BOB (107 CUI)NGK CR9EIX  
HARLEY-DAVIDSONSOFTAIL FAT BOB (114 CUI)NGK CR9EIX  
HARLEY-DAVIDSONSOFTAIL FAT BOY (107 CUI)NGK CR9EIX  
HARLEY-DAVIDSONSOFTAIL FAT BOY (114 CUI)NGK CR9EIX  
HARLEY-DAVIDSONSOFTAIL FXDR (DESTROYER) 114 CUINGK CR9EIX  
HARLEY-DAVIDSONSOFTAIL HERITAGE CLASSIC (107 CUI)NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONSOFTAIL HERITAGE CLASSIC (114 CUI)NGK CR9EIX  
HARLEY-DAVIDSONSOFTAIL HERITAGE SPRINGERNGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONSOFTAIL LOW RIDER (107 CUI)NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONSOFTAIL LOW RIDER S (114 CUI)NGK CR9EIX  
HARLEY-DAVIDSONSOFTAIL NIGHT TRAINNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONSOFTAIL NIGHT TRAIN (EVOLUTION)NGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONSOFTAIL NIGHT TRAIN (TWIN CAM)NGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONSOFTAIL SLIMNGK DCPR7ENGK DCPR7EIX1.0 MM
HARLEY-DAVIDSONSOFTAIL SLIM (107 CUI)NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONSOFTAIL SLIM (EURO 4)NGK DCPR7ENGK DCPR7EIX1.0 MM
HARLEY-DAVIDSONSOFTAIL SLIM SNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONSOFTAIL SPORT GLIDE (107 CUI)NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONSOFTAIL SPRINGER (EVOLUTION)NGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONSOFTAIL SPRINGER (TWIN CAM)NGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONSOFTAIL SPRINGER CLASSICNGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONSOFTAIL SPRINGER CLASSICNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONSOFTAIL STANDARDNGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONSOFTAIL STREET BOB (107 CUI)NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONSPORT GLIDE (FXRT)NGK BPR5ES-11NGK BPR5EIX-111.1 MM
HARLEY-DAVIDSONSPORTSTER 1000 (XLH / XLT / XLS / XLX)NGK B-6L (71-78)BPR6HS-10 (79-85)1.0 MM
HARLEY-DAVIDSONSPORTSTER 1100NGK DCPR7ENGK DCPR7EIX0.8 MM
HARLEY-DAVIDSONSPORTSTER 1200NGK DCPR7ENGK DCPR7EIX1.0 MM
HARLEY-DAVIDSONSPORTSTER 1200 CUSTOMNGK DCPR7ENGK DCPR7EIX1.0 MM
HARLEY-DAVIDSONSPORTSTER 1200 CUSTOMNGK DCPR7E (-07)NGK DCPR8E (07-)1.0 MM
HARLEY-DAVIDSONSPORTSTER 1200 CUSTOMNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONSPORTSTER 1200 CUSTOM (EURO 4)NGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONSPORTSTER 1200 CUSTOMNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONSPORTSTER 1200 CUSTOMNGK DCPR7ENGK DCPR7EIX1.0 MM
HARLEY-DAVIDSONSPORTSTER 1200 IRONNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONSPORTSTER 1200 LOWNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONSPORTSTER 1200 NIGHTSTERNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONSPORTSTER 1200 ROADSTERNGK DCPR7E (-07)NGK DCPR8E (07-)1.0 MM
HARLEY-DAVIDSONSPORTSTER 1200 ROADSTER (EURO 4)NGK DCPR7ENGK DCPR7EIX1.0 MM
HARLEY-DAVIDSONSPORTSTER 1200 SPORTNGK DCPR7ENGK DCPR7EIX1.0 MM
HARLEY-DAVIDSONSPORTSTER 1200 SUPER LOWNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONSPORTSTER 1200 SUPER LOW (EURO 4)NGK DPR7ENGK DPR7EIX 
HARLEY-DAVIDSONSPORTSTER 883 DELUXENGK DPR7EA-9NGK DPR7EIX-90.9 MM
HARLEY-DAVIDSONSPORTSTER 883 HUGGERNGK DPR7EA-9NGK DPR7EIX-90.9 MM
HARLEY-DAVIDSONSPORTSTER 883 IRONNGK DCPR7ENGK DCPR7EIX0.9 MM
HARLEY-DAVIDSONSPORTSTER 883 IRON (EURO 4)NGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONSPORTSTER 883 RNGK DPR7EA-9NGK DPR7EIX-90.9 MM
HARLEY-DAVIDSONSPORTSTER 883 R ROADSTERNGK DCPR7ENGK DCPR7EIX0.9 MM
HARLEY-DAVIDSONSPORTSTER 883 STANDARD / DELUXENGK DPR7EA-9NGK DPR7EIX-90.9 MM
HARLEY-DAVIDSONSPORTSTER 883 SUPERLOWNGK DCPR7ENGK DCPR7EIX0.9 MM
HARLEY-DAVIDSONSPORTSTER 883 SUPERLOW (EURO 4)NGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONSPORTSTER 883 / LOWNGK DCPR7ENGK DCPR7EIX0.9 MM
HARLEY-DAVIDSONSPORTSTER 900 (XLH / XLCH)NGK B6L 1.0 MM
HARLEY-DAVIDSONSPORTSTER CUSTOM 53NGK DPR7EA-9NGK DPR7EIX-90.9 MM
HARLEY-DAVIDSONSPORTSTER CUSTOM 53 / CUSTOMNGK DCPR7ENGK DCPR7EIX0.9 MM
HARLEY-DAVIDSONSTREET 750NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONSTREET 750 (EURO 4)NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONSTREET GLIDENGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONSTREET GLIDENGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONSTREET GLIDENGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONSTREET GLIDE (107 CUI)NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONSTREET GLIDE SPECIALNGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONSTREET GLIDE SPECIAL (107 CUI) EURO 4NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONSTREET GLIDE SPECIAL (114 CUI)NGK CR9EIX  
HARLEY-DAVIDSONSTREET RODNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONSTREET ROD 750 (EURO 4)NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONTRI GLIDE ULTRANGK DCPR7ENGK DCPR7EIX 
HARLEY-DAVIDSONTRI GLIDE ULTRA (EURO 4)NGK CR9ENGK CR9EIX 
HARLEY-DAVIDSONV-ROD (A-MODELL)NGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONV-ROD (B-MODELL)NGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONV-ROD / ABSNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONV-ROD 10TH ANNIVERSARYNGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONV-ROD MUSCLENGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONV-ROD MUSCLENGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONXLCR CAFE RACERNGK B6L 1.0 MM
HARLEY-DAVIDSONXR 1000 (SPORTSTER)NGK BPR6ES-11NGK BPR6EIX-111.1 MM
HARLEY-DAVIDSONXR 1200NGK DCPR8ENGK DCPR8EIX1.0 MM
HARLEY-DAVIDSONXR 1200 XNGK DCPR8ENGK DCPR8EIX1.0 MM

Reading your spark plug

spark plug colour guide 411x305 - Harley Davidson Spark Plug Cross Reference

The image of the spark plugs above shows four common conditions that you’ll find your spark plugs in. From left to right the plugs are Normal, Rich, Lean and Very Lean. Full descriptions below.

Before you throw your old spark plug in the bin, check them to get an understanding of how well your engine is running.

Normal condition

If the plug is brown or light grey your can assume your engine is in good condition and the spark plug is functioning well. Even when a plug is in good condition small deposits will accumulate. This is normal.

Rich

There are many different causes of spark plug fouling. If the plug has oil on it, then it’s oiling up and may not work efficiently, potentially causing a misfire or stuttering under hard acceleration. If it’s just dark or black the bike could be running too rich. A heavy accumulation of carbon on the nose can cause a leakage path to earth. This can cause misfires and poor engine starting.

Causes: The causes of this can be anything from, a rich fuel mixture, too much choke, long periods of low-speed riding or idling in traffic, a blocked air filter or the plug’s heat range is too cold.

Lean

If the engine is running lean then the spark plug has a grey colour but you’ll probably see some black deposits on there too.

Causes: Insufficient cooling, blocked injectors, too lean a fuel mixture

Very Lean

If the engine is running dangerously lean the whole plug tip will be grey or white. If the temperature is over 850-degrees, pre-ignition may occur. Engine power will be reduced and you risk piston damage.

Causes: Insufficient cooling, blocked injectors, too lean a fuel mixture, ignition timing too far advanced, excessive combustion chamber deposits.

Motorcycle Spark Plug Fitting Guide + Tips

  • When you’ve removed your spark plugs, check the condition of the threads in the cylinder head and put a cloth over the cylinder head if you’re going to leave it exposed.

  • Install each spark plug by hand until you have wound the thread a couple of turns. This reduces the chances of you cross-threading the plug.

  • Torque the spark plug up to your manufacturer’s recommended settings. If you don’t have a torque wrench, then get the plug hand tight and then add a ½ turn for a plug with a gasket, and more like a ¼ turn for a tapered spark plug. Over-tightening can snap the spark plug – a nightmare.

  • Don’t put any lubricant or thread lock on the spark plug. Inspect your spark plug caps and replace if required.

Iridium Spark Plug vs Standard

A regular spark plug uses a copper central electrode whereas an iridium spark plug uses, you guessed it, iridium.

The metal in a spark plug has a single purpose: to channel the electrical energy through the spark plug. Iridium is far harder than copper and this allows the spark plug manufacturers to create a plug with a sharper ‘tip’ which better focuses the spark around the centre electrode without compromising its service life.

A typical copper spark plug will last around 20,000 miles and most get changed at a major service (usually around 16,000 miles) but an iridium spark plug will be good for around 50,000 miles and you do see people running them to 100,000 miles with no issues.

Copper is generally seen as being the best metal to use in terms of conductivity but iridium plugs are seen as premium as they last longer than standard plugs and can be built with smaller tolerances. Iridium spark plugs also have lower voltage requirements, meaning they perform better when starting and idling and some manufacturers also claim they offer a better throttle response.

Iridium plugs are more expensive than copper but seeing as they last longer and offer a more consistent performance throughout their lifetime, many bikes opt for an iridium ‘upgrade’.

Spark Plug Removal

 

halfords socket set 500x202 - Harley Davidson Spark Plug Cross Reference

If you’re going to be doing any sort of work on the bike, treat yourself to a decent set of tools. Most of mine are from the Halfords Advanced range (formerly called Professional).

They have a lifetime guarantee and for an amateur bodger like me, they’re perfect.

The image above shows their 100pc range, which costs around £125. It’s a comprehensive bit of kit and includes a 1/4″, 3/8″ and 1/2″ drive, alongside plug sockets, universal joints and a wobble bar. Pretty much everything you’ll ever need for any motorcycle maintenance job.

Motorcycle Spark Plug Removal Tools

If you’ve not changed your plugs before, give yourself a couple of hours to complete the task. Here are the essentials you need for smooth re-plugging:

Your owner’s manual
You’ll need this to help you find the location of your spark plugs and how to access them. This may sound simple but often the manual offers up some time-saving tips for your particular model.

A spark plug socket
You’ll need a deep socket. A decent tool kit will have them. Don’t get confused between thread size and socket size. Motorcycle spark plug socket sizes are usually 16mm, 18mm or 20.6mm (21mm will do). Whereas the threads are usually 10mm, 12mm or 14mm. When it comes to motorcycles, access is usually tricky, so my tip is to buy a magnetic spark plug socket like this one. Once you’ve undone your old plug, this will help you remove it with far less effing and jeffing.

A wobble socket / universal joint
You’ll be lucky if there’s a straight line to your spark plug, so a universal joint will get you the angle you need to apply some torque. Again, a decent toolset will have one.

A 3/8″ drive
You could buy a specific spark plug T-bar but your home tool kit will have the drive you need to connect to your plug sockets.

A spark plug gap gauge
This nifty little tool only costs a few quid and will help you set the correct gap for your spark plug. However, modern plugs are almost all motorcycle-specific fit and so they come ‘pre-gapped’ and you won’t need to touch them. If you’re running a classic bike, you’ll probably need to set your gap and if your bike’s not running right, a gap tool can help you rule out a potential incorrect gap issue.

A torque wrench
It’s important to properly torque your spark plugs. Too tight and you’ll risk snapping it or it will be a mission to remove. Too loose and you risk an electrical short. Your owner’s manual will have the correct torque settings.

Motorcycle Spark Plug FAQ

What are the common motorcycle spark plug sizes?
Thread diameters of 10mm, 12mm, and 14mm are the most common. In fact, when it comes to motorcycles, it's rare to find any other sizes in use.

How long should a spark plug last?
Motorcycle spark plugs usually last around 16,000 miles, or at least this is when most manufacturer service schedules recommend you change them. That's typically once every other major service. However if you use Iridium spark plugs they will last a lot longer, usually well over 30,000 miles.

How do you clean motorcycle spark plugs?
Just remove the plug and use a wire brush to gently brush off any deposits on the electrode. Don't use a power tool, by hand is all that's required.

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