Rate my plug

[quad4me]

well estimated 6 hrs. They were in when I bought it. But from what I understand it was "tuned up" when he got ready to sell it. May be much much more.....easy solution= put in new ones, see how they do.

[Justintoxicated]

yea it might be lean then, need to use fresh plugs and do a WOT test.,, You might be rich on the needle and lean on the Main. etc

[canyncarvr]

Sorry. The plug doesn't tell much of anything. Maybe that the heat range is ok.

 

Mixture readings are done at the base of the insulator (which, as pointed out already, you can't see in your pic=). You can't see the base well at all unless you remove the threaded portion of the plug (hacksaw or pnuematic cut-off). There are spark plug viewers specifically designed to look down into a plug. Run about $50. Come with magnifying glass and a light.

 

You're looking for a ring at the base of the insulator. Commonly considered to be 'good' at about 2mm wide. Wider than that? Too rich. More narrow? Getting close to too lean. 1mm is optimum...but that's cutting it pretty close. Unless your jetted for THAT DAY..meaning a certain temp, elevation, riding condition and rider, a 1mm ring might get you into trouble.

 

You can read mixture tell-tales from the flat of the threads, too.

 

In any case, the carb has a number of circuits. Each will leave it's own 'mark' on a plug. That's why a WOT plug-chop is useful (for determining the selection of the main jet). Otherwise, with just 'riding around' you're using the pilot/air-screw circuit, the slide, the needle jet, the needle and the main in various combinations at different throttle positions.

 

The color you easily see on the nose of the plug is more related to proper (or not) heat range than anything else. You might see some evidence of fuel/oil additives.

 

Cheers!

[Banchetta]

Wasting your time w/o a wide open run in 6th gear. That pic tells nothing. A wide open run would not have a wet look w/ that color...