I have 8500mi on my RK; when and what kind of plugs to use.

 

My '07 SG is stock. I changed the 1st set at 19,000 and all I was running was slip-ons and XIED's. They looked fine.

I just put a new set in since I'm taking a long trip. I have had Fulsac true duals for about 1000 miles now, so 17,000 on this set and they look great too.

I just use the stock Harley plugs. Works for me.

 

Moco say's replace every 20K. I change Mine every 10K, and check them every 3K.

 

I use the standard H-D plug and change them about every 15-20k.

 

Do they look like ****...??? If they do change them....if they look ok leave them in.

 

Twin cams are a hell of a lot easier on plugs then the older Harleys were. I wouldn't think of changing them till at least 20k. When I do I run Autolites.

 

20k unless they look bad. At 8k they should look good

 

HD plugs every 10K.

 

I change mine once a season.

Overkill? It is. But I have to pull the plugs anyway to fog the cylinders when I'm getting it ready for the winter. It puts me in a slightly better frame of mind when I start looking forward to getting it on the road again in the spring.

 

I put a set in every year I do at least 10k a year and they are cheap you only need the stock plugs thats it. When I pull them they still look fine but it is just a maintenance thing I do can't hurt. If you want to the best 20 bucks you can spend at a HD dealer Screaming Eagle plug wires!