BSA Triumph Oil In Frame Singles Oil Filter(s) PN# 99-1179 19-4589 FB994/1

Engine / frame oil filter as used on Triumph and BSA oil in frame singles with FB type cartridge filter.

Maintain proper oil filtration and extend engine life on your vintage BSA and Triumph singles with this high-quality Oil In Frame Singles Oil Filter, engineered as a direct replacement for the original FB-type cartridge element. Designed to work seamlessly with the factory frame-mounted oil system, this filter offers modern reliability while preserving correct fitment and appearance for period-correct restorations.

This cartridge replaces BSA/Triumph part numbers 99-1179, 19-4589, and FB994/1, making it ideal for popular oil-in-frame models such as the BSA B25 and B50, as well as Triumph TR25 and similar single-cylinder machines from the early 1970s. If you’re servicing the oil system on a classic British single or finishing a restoration, this filter helps keep abrasive particles out of bearings, journals, and other critical engine components.

Key Features

• Direct replacement for OEM FB-type oil filter cartridges: 99-1179, 19-4589, FB994/1.
  
• Designed specifically for BSA and Triumph oil-in-frame single-cylinder models using the frame oil reservoir system.
  
• Helps maintain clean oil flow to the top end and bottom end, reducing wear and improving long-term engine reliability on vintage British singles.
  
• Ideal for routine service, engine rebuilds, and period-correct restorations where original-style filtration is required.
  

Fitment Information

• This oil filter fits BSA B25 and B50 oil-in-frame models (1971-on) and Triumph TR25/T25 singles equipped with the FB-type cartridge filter in the frame oil circuit. Always confirm your existing part numbers and filter housing style before ordering, especially on bikes with modified or upgraded oil systems.

The product images shown are for illustrative purposes only and may not be an exact representation of the product received. Manufacturers occasionally make minor cosmetic changes to items, such as color, finish, label, or design. These changes do not impact the item’s function or compatibility. Please contact us if you have specific concerns regarding appearance.