SPARK PLUGS

[tkm]

Does anyone know if there is a downside to leaving the spark plugs in the bike beyond 12k if the plug gaps are well within specks and the plugs themselves look like new.

[RideandDrive]

I do it and I have never had any ill effects.

[DJ Downunder]

My car has had the same plugs for the past 200,000klms..and it still runs fine..I wouldn't change them if they don't need it.

But they are only cheap..it may be worth it for the piece of mind..CycleRob should know the answer to this one.

DJ

[priapismic]

I don't worry too much about time or mileage intervals *IF* periodic inspections reveal that the tips are a nice, light tan color, and there are no deposits building up. I'll take a little fine grit sandpaper and lightly go over the tip and electrode, just for good measure, then stick 'em back in til next time. Any doubt or if they begin to look their age or have lots of carbon on 'em, they're easy enough to replace.

[single650]

It's not just the gap with plugs. Over time the ceramic absorbs combustion products which reduce its resistance. This reduces the spark efficiency.

It won't harm the engine but starting and performance will degrade over time.

[riders]

I changed mine at 30,000 miles and 60,000 miles on my twinspark 04 R1150R. On my and my wife's previous single spark oilheads I changed them at 18,000 miles. They never looked like they needed changed.

[Oilhead]

I just change them as specified in the manual but since it is so ridiculously easy to check the plugs on our bikes, I don't see the harm in putting back the plug if it shows no wear.

On some bikes like my CBR600RR, it is such a project to get to the plugs that once you get to it, you might as well as replace it....