Triumph Norton BSA 500 650 750 850 Auto Advance Spring SET 54417992 HEAVY DUTY BSA Memorabilia The Girling disc has been

The Girling disc has been designed to achieve a considerable weight saving over stock cast iron rotors

one lever forward off while parking

Typical left-hand controls: horn

copied from original parts

Triumph Norton BSA 500 650 750 850 Auto Advance Spring SET 54417992 HEAVY DUTY BSA Memorabilia The Girling disc has beenThis pair of springs are to suit just about all "automatic advance" ignition units fitted to unit British singles, twins and triples of the '60s and '70s. Heavier tension to cope with modern, lesser octane fuels, less issues with pinging. Original Lucas part number is 54417992. These springs are tested for tension, and are as original Lucas back in the day.