First, let me repeat that I'm no tribologist. I'm just some dude on an Internet Forum who's read a lot about this particular topic and (for some reason) wants to share some of what I have learned.
FWIW, I don't think the 4K limit is super critical except maybe for the first 100 miles or so, then the max-rev limit progressively increases from there. Avoiding highway speeds until after the 600-mile service is a good idea though.
If you just want to relax without thinking about break-in too much, here are simple "TL;DR" guidelines you can follow:
- Ride extra gently while the engine is warming up.
- Don't apply excessive load but also don't baby it too much.
- Avoid high RPMs and full throttle. [see note]
- Mix in some "engine braking".
- Vary the road speed and especially vary the engine speed.
- Avoid lugging by matching your gear selection with the road speed.
- Avoid carrying extra weight.
- Avoid very short trips and very long trips.
- Change the oil and filter at 600 miles and 2,000 miles.
[note] If you've been reading about the ultra-crucial importance of compression-sealing your rings to the cylinder surfaces ("seating the rings") and you want to do something about that, you can. Occasionally and briefly apply full throttle while at cruising speed. Follow each full-throttle spurt with some engine braking and easy cruising. A little of this treatment goes a long way; you don't need to flog your engine to seat its rings well.
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Mr Mike makes the main point, which is: You're trying to avoid galling and scarring that happens from excessive metal-to-metal contact between interfacing parts while those parts' mating surfaces are still in the process of conforming to one another.
The enemies are heat and, to a lesser extent, less-than-ideal lubrication. Lubrication is sub-optimal because the new parts are temporarily going to fit more tightly and less precisely than they eventually will after wear-in.
When mated parts are fully worn-in their contact pressure will be spread over a larger area and they'll remain separated from one another by an extremely thin film of oil.
You can see a different example of wear-in happening when you're bedding-in your new brake pads and rotors. The Conventional Wisdom Advice for bedding in street brake pads is to start out by taking it easy, and bed-in the pads gradually. You can visually inspect your rotors and see the progress as it's being made.
The wear-in process is forgiving. Put another way, you have something gain by being more methodical and moderate about it, but the bike is made strong enough to survive just about any treatment you throw at it.