Question is, how common. Reason I ask is because I have seen several posts where people suggest plugs when putting together the traveling tool kit. I don't recall ever having a plug fail abruptly on any vehicle ever. Just did the 20K service and replaced the plugs since it was on the maintenance schedule. Plugs looked great, very little erosion at all, almost a waste it seems to change them. Decided to save one, clean it, and include in the tool kit. Only 1 because I dropped one and broke the ceramic tip.

 

Never heard of a plug failing, just fouling out. If something starts causing your plugs to foul out, having a spare sets might help you limp home or to the dealer. That being said, I was getting check-engine light/diagnostics codes that were caused by the spark-plug screw-on tip being loose.

 

It's an old school Harley habit from the days when it wasn't uncommon for plugs to foul out for whatever reason (oil or too rich etc). I've never had it happen but It does happen.

 

When I installed the plugs, I didn't even check the tips but if they had been loose, I would have felt it especially when I put the dialectic grease on them,. Easy and quick check.

Sometimes things are done because they were "always done". It's in my tool box I will be carrying, so it'll stay.

 

Buy plugs with solid tops that dont unscrew.

 

I carry a used set on long trips up thru the mountains where a parts store is no where in sight...just 'cause ya never know. The only time I used them was when a rider was broke down due to fouling both plugs, I stopped & let him have them. Yeah, its an old habit from days gone by.

 

I've been carrying spare plugs on my bikes since 1969. A couple of times I fouled plugs on my Norton Commando somewhere around 1975. Never fouled one since. I am convinced, however, that if I stop carrying a set of spares, I'll need them the next day.

 

I don't carry spare plugs anymore or even light bulbs. Even if you don't have LEDs their is always a gas station that carrys bulbs. I don't even carry a tool pouch anymore, just a Leatherman. And it's a good thing it's stainless.

P.S. Other than the Leatherman I do carry a Tire pressure gage, Fuses, Flashlight and a Plug wrench.

 

I replaced mine at 42k, they looked brand new. Dont think its a problem with the newer bikes, but it wouldn't hurt to carry a couple spares

 

spare plugs don't take up much room-

I sometimes have needed them on antiques.

I carry a tool roll, the plugs make it complete.

spare plugs are gapped and ready to go, with a little antisieze on the threads

mike