Home Shop Ignition Spark Plugs Spark Plug #2: IOE, 45”, V models and Knuckleheads
Click here to recommend this page to others

Spark Plug #2: IOE, 45”, V models and Knuckleheads

... more
less

Spark Plug Heat Ranges

Harley spark plug heat ranges are marked by numbers, from 2 to 12. No. 2 is the hottest plug, no. 6 would then be a relatively cool plug. The coolest plug used by Harley-Davidson is marked 10R12A. Double numbers characterize multi-range plugs.

With older motors, it was not uncommon, that you achieved an optimum with plugs of two different heat ranges. Unlike the well known prejudice implied, you had to choose cooler plugs for the front and hotter plugs for the rear cylinder. On later Harley engine designs, heat distribution is balanced to such an extent that you should not have to rely on those tricks anymore.

Stroker owners should refer to OEM instructions for their specific type of motor, unless the manufacturer recommends entirely different plugs.
Spark plug, fits IOE models 1927-1929, Singles 1926-1934, 45 cui/750 cc Flathead →1955 (exc. K-models), V models and Knucklehead, thread: M18 x 1.5, thread length: 1/2 ”, wrench size: 7/8 ”, OEM labelling: 2, replaces OEM 32304-09, and 37-09B
W&W# Picture Price incl. VAT* Available from warehouse Germany?
12-028 Spark Plug #2: IOE, 45”, V models and Knuckleheads by Champion, manuf. labelling: UD16 6.07 € each
in stock
* The price includes German VAT (19% or reduced rate of 7% for Books).

Accessories:

  • Spark Plug Boxes

    Spark Plug Boxes Reproduction of the spark plug holder used on models from 1940–54. Clamps onto frame tubes.

  • Air-Cooled Spark Plug Cover

    Air-Cooled Spark Plug Cover With prices for original air-cooled spark plugs skyrocketing, this little conversion kit will be comparatively easy on your budget. It converts conventional ...

See also:

  • C. Walter Spark Plug Wire Brushes

    C. Walter Spark Plug Wire Brushes Don´t get caught without it! This little brush should be part of any tool roll or tool box. Cleans sooty plugs in seconds so you are back on the road in no ...

  • Loctite 8065 Thread Lubricant

    Loctite 8065 Thread Lubricant Copper paste stick to lubricate threaded connections. Compared with liquid counterparts these sticks with semi-solid consistency offer some advantages: optimum ...

Have any questions?

  • Our sales team will be glad to help out:
    Mondays - Fridays 08:00-18:00 CET, Saturdays 09:00-13:00 CET
    Phone: +49 / 931 250 61 16
    eMail: sales@wwag.com