Certainly they can get the 961 through the next level of emission regs. But this will require, lower CR, larger Cats, change in cam and ignition timing. It will mean a drop in HP and performance. So, Norton will reach a point of no return with the air-cooled 961:
Can they sell a 961 that meets Euro 6, but has its performance compromised to the extent that it makes perhaps 60-65HP? Possibly, look at the Royal Enfield and their lower HP, they sell, so perhaps this would work for Norton too.
Is it worth the effort to re-engineer the 961 to meet Euro 4,5,6? Probably not.
If Norton feel that the 961’s connection to the Norton legacy of the past is important to maintain, then they should go the route of Triumph’s 900/1200 modern classics. Give the job of redesigning the 961 into a liquid cooled machine to Ricardo. Design out of the engine all of the problem areas, but keep the look as close to classic Norton as possible.
If they don’t want to redesign the 961/Commando for future survivability in the world of future Euro regulations, then retire the whole 961 family, and take the new 650 motor, and create a “Classic” 750 variant with faux cooling fins on the head and cylinders, and engine covers with a vintage shape/style. The insides of the motors will be identical to the sport 650 line using the same parts.
Viola – the new 750 Commando II !
If the new Norton Scrambler 650 has 82HP, a 750 variant (stroked) could produce 90HP. That would make for a better performing Commando than the 961 is today. Plus Norton get to continue the Command/Dominator product name into a new generation of vehicles. This will enable them to attract old timers to the new product, and younger riders who value high performance that may be interested in classic styling.