Norton mushroom tappet adjusters 750 850 Commando NMT2074 valve adjuster screw BSA There are other unit twins

There are other unit twins that are not mentioned so if you have points on the side of your engine and have a stator

You will receive a brand new full sized parts book for your 1979 T140E Bonneville

This is the best stuff available for your motorcycle

These are high level and both go out to the left side

Manufacturer Part Number: PR4

Norton mushroom tappet adjusters 750 850 Commando NMT2074 valve adjuster screw BSA There are other unit twinsYou will get the adjuster that is pictured. You receive 1 USA made Mushroom Tappet Adjuster as pictured. This adjuster is made of high carbon steel hardened to 58 60 Rockwell. The radius is machined to a #10 #16 micro finish. These adjusters add life to valves and guides by compensating for the poor geometry in the original design.