I have an '05 Ultra Classic with FI. What sort of life should I expect for the sparkplugs? Should I just figure on replacing them once a year, or go by a fixed mileage?
Thanks!

 

I do mine on my '03 @10k intervals. No issues in 84k.

 

10K is fine if it is tuned correctly. Some think they have a two stroke engines and change them more frequently.

 

Harley-Davidson recommends replacement at 10,000 miles. However, if I didn't put 10,000 miles a year on the bike, I would change them yearly.

 

I've replaced them 4 times in 35,000 miles.It didn't look like I needed to but,with only two required,it didn't cost that much!

Preventive maintenance I guess.Every time I replaced them was before a 3k or longer trip.

I went with AutoLites on the first change and stayed with them.
I kept them as spares after the 2nd change.I probably could still be running them!

 

10k sounds about what I do as well.

 

i change mine every year and i also carry spare set in my bags its a cheap replacement that can have detrimental consequences on the road if they go bad harleys dont push very well.

 

Once a year, plugs and wires for all the toys....even my Jeep.
$30 last month for stock harley plugs and 10mm screaming eagle wires (red plug wires to match my bike) I make sure the plugs are gap'd right before install too.

 

I change my plugs every 5,000 miles when I do the rest of the service. Cost less than $5 a pair.

 

I've replaced mine 3 times in 55K. I don't know what the big deal is. If it starts missing, I'll feel it and replace the plugs. Actually, it has never actually needed the plugs replaced yet.