Dual spark plugs

[joeb]

Hi all. Being new to the 1200 hex head I do have a question about the dual spark plugs.

How do you know if one went bad ?

Would I notice anything while driving ?

[dirtrider]

42 minutes ago, joeb said:

Hi all. Being new to the 1200 hex head I do have a question about the dual spark plugs.

How do you know if one went bad ?

Would I notice anything while driving ?

Afternoon  joeb

 

Typically spark plugs don't just "Go Bad".

 

But to answer your question, that DEPENDS on what spark plug is not working correctly. The lower spark plugs mainly effect lower RPM's & idle quality. 

 

The upper plugs effect both the low RPM, mid RPM, & especially the higher RPM under road load.

 

Way more apt that you have a coil causing an issue then a spark plug.

 

If you are worried then see if it will run on JUST the uppers (disconnected lowers, then see if it will run on just the lowers (uppers disconnected).  When doing each of the above also see of both side front exhaust pipes are about the same temperature  (no cold pipe on one side) 

[joeb]

Great ideas. Thanks much