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Spark Plugs #3-4: Big Twin 1948-1974, KH+XL  1954-1978

Spark Plugs #3-4: Big Twin 1948-1974, KH+XL  1954-1978

Select variant:
12-012
by Champion; manufacturer-code: RJ12YC
12-081
»OEM«; Mexico
Price and stock:
Item №
12-012
Price incl. VAT
5.11 €
Available
100+
Ready for immediate delivery from our Würzburg, Germany warehouse
The price includes 0.82 € German VAT.
piece
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  • Spark plug by Champion
  • fits Big Twin 1948-1974, KH+XL  1954-1978, Servi-car 1956-1973
  • porcelain / steel
  • thread: M14 x 1.25
  • thread length: 3/8 ”
  • wrench size: 13/16 ”
  • manufacturer-code: RJ12YC
  • replaces Harley-Davidson part number HD 32303-47A, 32305-48A, and 32301-60
  • gross weight: 60 g

Champion Spark Plugs

Stock replacements since decades with proven performance. Excellent value.

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.

Have any questions?

Our service team will be glad to help out: Mondays - Thursdays 08:00-17:00 CET, Fridays 08:00-16:00 CET, Phone: +49 / 931 250 61 16, eMail: service@wwag.com