What would be the best spark plug replacement for my 08 nightster. I looked up the specs, but I'm not sure what to get......

 

Check out the link below for cross references on spark plug numbers. There is a lot of debate on the subject, but the stock harley spark plugs are just fine for your motor. And they are cheap.

http://www.nightrider.com/biketech/hdsparkplugs01.htm

 

Spark plugs are spark plugs. They have one job to do and no matter how much money you spend on plugs they won't make a difference in he way your bike runs.

 

Plugs aren't something to sweat over, when it comes to performance/gains...stick w/HD and you're good.

 

Only exception I can think of is Iridium plugs will last three times as long and are only twice the price (autolite XS4164). The ONLY reason I even tried them is for cold starts in the winter. Starting at 14F is much easier on the bike with the Iridiums. If you are not starting in such cold conditions then stock plugs are just as good. If I were not a year round rider I would aslo use stock plugs. They work better than some fancy plugs that cost more per plug than a quart of scamsoil.

 

I would actually recommend the non-HD equivalent. Same plug no HD branding or price gouging.

 

Take your pick of equivalents:

Champion RA8HC
NGK DCPR7E
Autolite 4164
Bosch YR6LDE
Denso Iridium IXU22

I pay less than $2.00ea for the Champions at the local auto parts store.

 

Autolite 4164's are very inexpensive, work great, and are made in the USA.

 

stock plugs are 4 dollars each. get the stock plugs

 

Funny i just got 2 new E3.36 plugs at O'Riellys today for my 2013 Sportster 72. I've got E3'S in my Softail, my Mustang & my F150 THEY improved performance in every vehicle & mileage in both cars. Just smoged both cars after installing E3's they got best #'s than ever on the tests. They're expensive but better than anything I've used before & I've tried everything