Re: Iridium plugs whats the view?
Posted by Nigel B on November 15, 2021, 8:11 am, in reply to "Iridium plugs whats the view?"
I have used them in RE Bullets & occasionally in MZs. Always have had to tweak the carb settings after fitting one - tickover usually increases & mixture can be weakened a bit from the pilot screw, as the iridium plugs ignite a weaker mixture more reliably. |
Last one I fitted was to the Classic 500, which had a bit of a misfire on the way home from picking it up. Put in a Denso Iridium (good price from Ebay - £8 delivered IIRC) & no issues since, though I did notice that the clutch interlock switch connector at the handlebar lever was possibly loose when I swapped the standard handle bars back. Tickover might be a bit high now, but no tacho & warnings on the UCE models not to set the tickover too low or the auto decompressor can engage.
Various MZs have run better with paladium or iridium plugs fitted - no fouling issues & long life. With the MZs I usually fitted non-resistor plug caps, as iridium plugs always seem to be resistor type, but for the Classic 500 this wasn't an option due to the shape of the OE cap (long reach type) - Denso literature suggested that it would be OK to use the iridium plugs with resistor caps & I have had no issues over the 1700 or so miles I've put on the bike since fitting the plug.
Denso plugs can be less expensive than NGK & I have found them to be reliable - easy to find a cross-reference table for the part number. Plus Denso originally developed iridium plugs & their centre electrode is finer than the NGKs. Originally developed for the Honda NSR500 GP two stroke race bikes to cut high speed misfires - apparently got another couple of hp per cylinder using them.
Only the initial cost to grumble about, but with the longer life probably work out cheaper overall than changing standard plugs more regularly.