The pipes were originally to give an oil feed to the exhaust camshafts which were experiencing quite rapid wear.
A similar problem existed in the twins which also got an extra oil feed to the exhaust camshaft (cant remember if the inlet camshafts got them too).
The camshaft wear problem was eventually solved by nitriding the camshafts and the auxiliary oil feed was deleted.
This was advantageous as the triples oil feed to the camshaft(s) took oil away from the main bearings.
The Service Bulletin referred to involves cutting off the pipes just above the main bearing and squashing the cut end of the pipe to seal it off.
Later triples did not have the pipes fitted from the factory so nothing to do on the later bikes.