Useful Alternative Parts for the Sportster

Here are some alternatives to the HD parts for your Sportster.

Spark plugs

Autolite 4164 - Works just as well as the HD spark plug, but costs $1.50/each or so and is widely available in most auto parts stores.  Set the gap between 0.038" and 0.040".  The wrench for these spark plugs is not one of two standard spark plug wrenches.  It is either 13/16" or 18mm.  I am not sure if it is metric or SAE, but in this particular size either metric or SAE will work just fine.  Remember, you do not need a socket wrench for the Sportster!  A box wrench will work fine.

Champion RA8HC with '810' on the end of the box is most like the HD plug according to many posts on Sportster.org. The gap is .039" - .040".  Use a .038" dia. and a .040" dia. wires from a plug gap tool.  Set the gap so the .038" dia. gage goes thru easy and the .040"dia. gage will not go through.

Oil Filter

Pure One by Purolator PL10241
Pure One by Purolator PL25230 longer if you can use it
Mobil M1-102
Bosch 3330
Wix (& NAPA) equivalents of #51348 and 51315 (longer).
NAPA 1215
Ford (Autocraft) F1A or FL-1A

Air Filter

K&N replacement for the stock air box: HD-8834
K&N replacement for the HD Screaming Eagle air box: HD-0900 
K&N High flow air box kit with filter: RK-3929
Drag Specialties replacementfor the HD Screaming Eagle air box: 1011-0783