Pablo's gs500 page
Spark plug information
R1 taillight install on 89-00 gs500
Clear Taillight Lens for 01-03 Models
My Local Canyons
What's it worth?
Progressive fork spring install-the lazy way
Rear shock swap information
More rear shock info-SV650 install
Suspension tuning 101
Installing Suburban-Machinery SV650 handlebars
Install an SV650 headlight
Converting standard 1/4 throttle to 1/5 throttle
Installing LED's in stock taillight
Uber Fender Eliminator
R1 Taillight on 89-00 GS500
Speedo/Tach light replacement
Better handlebar grips
Installing Buell turn signals - Rear
Installing Buell turn signals - Front
Flush mount rear (stock) turn signals
Installing a 2001 Ducati Monster fairing
Fix a broken oil filter cap bolt
General battery info
A Wal-Mart sealed battery?
Chain Maintenance
Installing SV650 Chainguard
Spark plug information
Installing a GSXR front end
Installing a GSXR swingarm
Installing GSXR rear passenger peg brackets
Installing an OEM Bandit 400 rear hugger
Installing a Bandit 400 rear wheel
Installing a GSXR rear wheel-simple swap
Polishing your wheels
"The Mystical Art of Tire Reading" and other tire info
General tire info for the GS #1
General tire info for the GS #2
General tire info for the GS #3 - mixing brands/types
gsJack's opinion on tires for the GS
Gearing and sprockets
Slip-on mufflers
Slip-on exhaust : using stock SV650 muffler
Installing an R6 tail
Installing GSX-R600 stock rearsets
Installing CBR600 stock rearsets
Replacing stock front pegs with CBR pegs
Replacing stock front pegs with Katana pegs
Why re-jet a stock US bike
More on re-jetting your carbs
Jetting for 2001 models

Regarding spark plugs...

Standard heat range Spark Plug (per Clymer manual): NGK DPR8EA-9;  gap 0.7-0.8mm


On the 3 recommended spark plugs. One is labeled standard (as above), one labeled hot, and one labeled cold.  Which is the best choice and why?

"Heat" ranges do not mean ambient temperature. They relate to the temperature range the spark plug tip experiences while the engine is running.

A "Cold" plug is manufactured so the electrode is just peeking out of the ceramic insulator. This way, the spark plug tip is "cooled" quicker by heat transfer to the head. Racing engines, or engines running octane boosters often use these.

A "normal" heat range is between "cold" and "hot". Normally there is more than one range in the middle.

A "Hot" heat range has the electrode sticking farther out from the ceramic insulator. This causes the electrode to run hot.  A good use of this is an engine that burns oil. You want the electrode to "burn" itself clean. A good use of this is a two-stroke, where you mix oil with gas. A bad use of this heat range could be a hot spot in the cylinder. It could cause the fuel/air mixture to ignite BEFORE the spark, causing pre-ignition.  The worst use of this heat range could possibly get SO HOT, to melt the dome of the piston a little each fire. The result is it burns a hole in the piston.  Two strokes have this problem more than four, because the "philosophy" is usually different.

Pick the COOLEST plug you can run in a four stroke, and still do the job (plug light brown).
Pick the HOTTEST plug you can run in a two stroke, and not damage the system (plug light brown)

Thanks to Kerry Burton for this info-fromthe archives