- fits IOE models 1927-1929, Singles 1926-1934, 45 cui/750 cc Flathead →1955 (exc. K-models), V models and Knucklehead
- porcelain / steel
- thread: M18 x 1.5
- thread length: 1/2 ”
- wrench size: 7/8 ”
- connection thread: M4
- heat range: manufacturer-code UD16 corresponds to HD-code 2
- replaces OEM 32304-09, and 37-09B
- gross weight: 80 g
Champion Spark PlugsStock 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.
Cooling Rings for Spark Plugs
PanAm Spark Plug Wrenches
Spark Plug Boxes
C. Walter Spark Plug Wire Brushes
Loctite 8065 Thread Lubricant
The Cyclery Spare Plug Holders for Classic Springer Forks
Permatex Tune-Up Dielectric Grease
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: firstname.lastname@example.org