pd110961 - the running in really, really does mean 35-40 mph maximum for the first 300 miles (first service time when the bike should be fully checked over).
Thereafter 45-50 mph max to 600 miles. Service intervals are done in kilometres - 500km (1st/full monty), 3000km (check/adjust), 6000km (oil change) and so on [500km = 300 miles]
I got my bike from Hayballs in Salisbury, paid cash in full, they've been in the m/c business since the 60s, love british classic bikes and know what they're doing with them. I was impressed by their mechanic. I'm an engineer, it takes a lot to impress me
You will feel the motor loosen up. Not everyone can feel and hear what a motor is going, it's an acquired art. I reckon it's as sweet as a nut but not fully run in yet.
Even now with 1000 miles on it I don't hold it on full throttle. That brief 75mph on my vid on the roman roller-coaster road was only about 70%, the tacho saying it's about 4200rpm, red line is what, 5500rpm(?). I believe the ecu has a rev-limiter, I've not found it (yet).
Some of the key issues when running in is feeding the power in gently, limiting the revs, not letting it slog or knock bottom. Fourth gear knocks bottom at 30mph, no good. Third gear is maybe a little high for 30-mph depending on yo-yo cage traffic and Gatsos. In other works don't let the motor work hard.
Otoh that's doesn't mean drive like your granny in a supermarket car park, the bike has a fair bit of poke even being gentle with her. Even with 'only' 27bhp it is defo not a 125cc. Ride along with a jap twin and you'll hear them swapping cogs every two seconds whilst the Bullet power band just goes on for ever. It's very flexible, you don't have to keep changing gear.
The power shoots up around 4500 and the exhaust note changes to a higher pitch bark, at the moment that's telling me to change up.
Looking at the oil can also tell you what's going on. At present the oil is lovely and clean with no nasty bits in it.
Most new cars engines are pre-run in at the factory on gas. So not the case with these bikes.
You do not do the initial running in over 40mph, the engine is too tight and will damage it.