Spark Plugs

The owner's manual recommends changing the spark plugs every 8000 miles. I decided to try out some Denso Iridium Power. Although ordinary spark plugs are not that expensive, the Denso last for ages (I replaced mine after 32000 miles although they still looked perfect). They cost around twice the price of standard plugs, but last roughly four times as long, so they're actually more economical.

The central electrode of these plugs is made of Iridium, an incredibly hard metal, and therefore this electrode can be made with a much smaller diameter - 0.4mm. This creates a more efficient spark because the spark is more concentrated at the tiny tip. Not only that, less spark plug voltage is required.

I've noticed that since installing the Denso, ignition appears to have improved, and fuel economy is better. I won't go back to standard plugs!

Return from Spark Plugs to Repair and Maintenance
Return from Spark Plugs to ST1100 front page
Top of page