PBI Portco USA 25 Tooth Transmission Mainshaft Sprocket Harley 4 Speed Big Twin
Brand: PBI / Portco USA
Part Number (Ref): H-37-25 (Cross-references to PBI 279-25)
Tooth Count: 25-Tooth
Chain Size: Fits 530 Pitch Chain
Material: High-grade Chromoly Steel
Finish: Electroless Nickel Plating (for corrosion resistance)
Manufacturing: Made in the USA
Model Compatibility
This sprocket is a direct fit for Harley-Davidson 4-Speed Big Twin transmissions, typically covering the following years and models:
Era Compatible Models
1936 – 1947 Knucklehead (EL, FL)
1937 – 1948 Big Twin Flathead (U, UL, ULH)
1948 – 1965 Panhead (FL, FLH)
1966 – 1979 Shovelhead (FL, FLH, FX, FXE, FXS)
Note: This 25-tooth configuration is often used to achieve higher top-end speeds and lower highway RPMs compared to the stock 22 or 23-tooth sprockets
selling as pictured.
more than welcome to pick up at shop in butler pa & save shipping.
031126hb