This petcock features the proper 1/4 inch BSP (British Standard Parallel) threads for Triumph, BSA and Norton motorcycles, as well as any others with the BSP threads. This ‘flag’ style petcock is original equipment for Triumph 750cc models such as T140 and TR7, as well as Norton 750 and 850 cc motorcycles. This petcock does not have a reserve feature, and is considered the main petcock. Replacement for OEM # 60-4511