LOL! You don't want a street bike? What do you think a Harley is, a dirt bike? 8^)

A Honda Shadow is a good place to start. 750cc, about 45 or 50 hp (I could be wrong). Harley is making a new 'Street 750' and 'Street 500' which are very similar to a Shadow, which might be perfect except you shouldn't (IMO) learn to ride on a brand new bike. The Shadow's been around forever so you could get a very nice used one fairly cheap.

Or a Kawasaki Vulcan 800 or 1100, or a Suzuki C50 or M50, or I think Yamaha Star has something in the 800-900 size range.

This size, between 750 and 100cc, would be too big to start on a standard bike but cruisers have a very low center of gravity so the bike feels much lighter than it actually is. Plus bigger ones are not necessarily faster, the size is for stability and stamina on the highway.

A Sportster would be okay too, after all, that was Harley's 'entry level' bike for several decades before the Street 750 and 500 bikes came out this year. I think it's kind of a clunky bike, but they are VERY popular, especially with beginners, so WTF do I know? 8^P In comparison reviews the Sportster always comes off as the slowest, clunkiest, least comfortable bike in the class. (Look on YouTube for 'cruiser comparison test', 'cruiser shootout', etc.)

Cruisers are relatively easy to ride and also relatively safe, because they support a relaxed, laid-back riding style. A cruiser would be good to learn on even if you wanted to graduate to a sport bike!

Not exactly normal, it all depends on those 470 miles beforehand.
The break-in is there to give the engine some 'room' to stretch, if you pushed that stretch a bit too much there could be a bit of internal damage to the piston rings.
Best to make that appointment soon for it's first tune-up.

6.5 hp predator engine v.s. 2.5 hp 4 speed dirt bike engine.s?

im looking to build a racing go kart and i cant diside if i want to go with a 6.5 horsepower 212cc predator engine or if i want to go with a 50cc 2.5 horsepower 4 speed dirt bike engine.
which will be more powerful and which will be faster. they are both 4 stroke engines but the predator 212 only reaches 3600 rpm were the dirt bike engine will reach 7000 rpm.

The R6 is a bit taller than the Ninjette, so you will physically fit better.
The R6 has considerable more torque and horsepower and will be quicker off the line and has a far higher top speed.

But if you want want "pick up" meaning quick acceleration off the line when the traffic signal goes green... ah... a girl on a beginner 30 bhp 85 mph Suzuki S40 "cruiser" will leaving you behind. Sport bikes are for track, the twisties, playing on the super slab. If you to want play in stop and go city streets, any "sport" bike is pitiful.

The embarrassing possibility is that the kill-switch is switched on. Easy to do.

It is always worth checking the battery with a multimeter yours might not be charging or faulty.

Failing those then it is probably an electrical connection either shorted, corroded or not earthed properly.