09-11-2014, 03:41 PM
(09-11-2014, 12:08 AM)The ferret_imp Wrote: I have never had a plug break down and misfire. I replaced the plugs in my ST at 25,000 miles but the plugs that came out looked just like the plugs that went in. Many on the ST board run them 50,000 or more.
I suspect I will inspect the ones in my CB at about 20,000 miles, unless it starts misfiring, or gets hard to start, or my gas mileage drops off.
This is what I've always done. I pull 'em every few years to clean and gap, then put 'em right back in.
The CB750's stock plugs went 25K miles. The electrodes still looked fine, but one of the plugs developed a hairline crack in the ceramic and started to misfire.