M 8 Spark Plugs

[Jack Klarich]

NGK part number for M8 engines is

CR9E

Iridium # CR9EIX

I dunno if I can justify paying the extra for Iridium

This is an alternative to the HD plugs

Seems these odd ball plugs fit a lot of Japanese made bikes HMMMMMMMM

 

[MDO]

I have always liked NGK plugs, but I'm so happy with the way this new 107 runs, I may stay with the stock ones if they look good after 2 years.

 

[MDO]

Have you pulled your plugs yet & if so, how did they look?

 

[rhino 2]

Its not like the old days plugs last 30 thousand plus miles...When gas was leaded maybe 12 thousand miles...I checked the plugs on my 2011 Tri..[103] at 40 thousand they were like new, And the gaps were within specs... The M8 Should last at least that long what with two plugs per cylinder...

Back in my drag racing days i would change them out after 4 or 5 1/4 mile runs, But they were moderfided by me. [Cut back] Should have patented the idea...

 

[MDO]

Regarding the M8, Has anyone pulled the plugs yet & if so, how did they look?

 

[MDO]

NGK part number for M8 engines is

CR9E

Iridium # CR9EIX

I dunno if I can justify paying the extra for Iridium

This is an alternative to the HD plugs

Seems these odd ball plugs fit a lot of Japanese made bikes HMMMMMMMM

I notice your insinuation there, but I don't see Made in Japan stamped on the M8.

My 2005 Honda Sabre has 2 plugs per cylinder. Honda has been doing it for awhile on a lot of their bikes.

 

[Jack Klarich]

Regarding the M8, Has anyone pulled the plugs yet & if so, how did they look?

I notice your insinuation there, but I don't see Made in Japan stamped on the M8.

My 2005 Honda Sabre has 2 plugs per cylinder. Honda has been doing it for awhile on a lot of their bikes.

I have looked @ my plugs

They are burning light gray not white The M8 runs not as lean as the Twin Cams that is good for us

I probably wont change em til 30K

I believe NGK is a good global company

They make many apps for their plugs

 

[HDMAN]

Plug gap

NGK part number for M8 engines is

CR9E

Iridium # CR9EIX

I dunno if I can justify paying the extra for Iridium

This is an alternative to the HD plugs

Seems these odd ball plugs fit a lot of Japanese made bikes HMMMMMMMM

Jack what gap did you use for the iridium plugs. Thanks

 

[MDO]

This is from the 2017 service manual Table 2-18. Spark Plug- All Models M8​
TORQUE​	GAP ​		PLUG TYPE​
89–133 in-lbs (10–15 N·m)	0.031 –0.035 in (0.8–0.9 mm)		HD-6R10

 

[Jack Klarich]

Jack what gap did you use for the iridium plugs. Thanks

My gap was @.032 That was my 15 Freewheeler with the 103 engine

Not changing plugs in my 17 M8 til I have a problem

This is from the 2017 service manual Table 2-18. Spark Plug- All Models M8​
TORQUE​	GAP ​		PLUG TYPE​
89–133 in-lbs (10–15 N·m)	0.031 –0.035 in (0.8–0.9 mm)		HD-6R10

Good post Michael