Senior VR Member
Join Date: Jul 2008
Location: Second Star to the right, then straight on till morning.
Thanked 2,027 Times in 1,360 Posts
Generally, hotter spark plugs are used in an engine that is running rich or uses oil. The hotter plug burns the contamination off and keeps the plugs from fouling.
Any soot around the base of the plug is just that. It does not indicate the running condition of the engine. What you should be concerned with is the condition of the electrode tip and the surrounding insulator.
A grayish tan to while color on the insulator and tip indicates the correct spark plug is in use, the fuel and ignition systems are in good shape and overall engine mechanical condition is good. Soft, black, sooty, dry-looking deposits on the tip and insulator indicate a rich air fuel mixture, weak ignition or wrong heat range spark plug (too cold). That is when you would consider changing to a hotter spark plug.
Current Bikes ---->
- 1969 Indian MX125 -10-2009 to Present
- 2008 Yamaha FZ6 - 11-2008 to Present
- 2006 Star Virago - 05-2011 to Present
- 2014 Honda CTX1300 - 05-2015 to Present
Past Bikes -------->
-1973 Yamaha RD350
-1991 Harley Sportster 883 XL
-2000 Yamaha XV125
-2003 Piaggio Fly
-2004 Suzuki LS650
-2005 Boulevard C50 - 07-2008 to 5-2012
-2012 Vulcan 900 05-2012-05-2015