The upgrade posts seen to be popular, so I’m gonna haul off and do it again.
I’ll let the proverbial cat out off the bag up front here so you can go off and do something more interesting without being obligated to read the rest of this. The best upgrade is to NOT upgrade your bike.
At their best a street rideable Commando isn’t going to make more than 50hp, so don’t try to make it something it isn’t. You can go whole hog and install high compression pistons which will do their best to hammer the lower end apart. You can install high lift cams which will do more damage by putting the horsepower even further up the RPM scale and weaken the bottom end even further. At most you’re going to gain a few ponies in a very narrow range and still get blown off by a poorly ridden Japanese 600.
In their prime, Norton lower ends were not the strongest and now the ticking time bomb of a filthy sludge trap and crankshaft cheeks that are developing cracks everywhere are just waiting to perforate the engine cases.
Keep these bikes running by not torturing them. They run great when they are rebuilt to stock specs with a modicum of care. The torque alone is more than adequate to keep a sane rider happy. They handle pretty darn well when the isolastics are shimmed up to where they’re supposed to be.
So leave well enough alone and keep them stock.
