Bmwdumptruck
Well-Known Member
Found this explanation of why dealers are being made to change plugs at low mileages On Ukgser.
Many manufacturers are now telling us to change our spark plugs at 7500 miles. Even though the spark plug manufacturers themselves claim a lifetime of FIVE TIMES that figure. Even iridium plugs, which could really last 100,000 miles. It seems utterly insane. And it is.
"SERVICE SCAM" I hear you cry. And that's what I always put it down to until I learned something very interesting whilst on a training course for one of the big Jap manufacturers.
It seems you can really blame this on tighter and tighter emmissions laws. And a thing called "In use complience"
A motorcycle has to meet it's Euro 4/5 criteria for the service life of that motorcycle. Not just when it's brand new. The fines and repocussions of falling foul of emmissions standard are HUGE. Just ask Volkswagon.
So the manufacturers are telling you to change your plugs so soon because under very rare circumstances (starting and stopping the engine constantly. Super short journeys in cold weather etc) the plug could foul to a point where the emmissions standard won't be met. Even though the plug is totally fine for the safe running of the engine, and could be de-carbed with a blast down the motorway, if the bike was randonly tested in this circumstance, the manufacturer could be fined or forced to recall their machines.
Changing the plugs so early helps to avoid this rare eventuality. Or maybe knowing a lot of people skip this 7500 plug change gives them reason to shirk off responsibilty.
So there's nothing wrong with your plugs at 7500 or even 12,000 miles. And you don't really need to change them. I for one will be recommending to my customers to double the service internal of their plug changes. The amount of beautfully clean (as new) expensive plugs I chuck in the bin always bothered me and made little mechanical sense.