You might add unless you want your bike to run right and sound right for longer than a season or two. A badly worn chain and not from worn gears? You absolutely cannot have one without the other. One half of that setup is just as important as the other half in theory and practice. But doing a half ass job does sometimes save you some money and work and it will get you down the road in this case. The ignition timing bouncing all over the place matters little to some that seem to be happy with it running and rattling down the road just good enough. Some airheads are proud of the fact that their engine sounds like someone shaking a rattle can of spray paint and yet somehow still runs . . . barely. Nothing at all wrong with that as long as they don't start blaming the machine for their own ways. It's just not my style and I recommend otherwise.