Why is my motorcycle smoking?

I recently bought a 1988 Honda shadow vt800c and now after long rides a small amount of what appears to be white smoke comes from the exhaust pipe. If I turn the bike off for a minute then back on it stops. Could this be from a coolant leak? It is low but I hadn t been monitoring it closely. Also we got gas all over the bike while fixing a fuel hose but washed it pretty well with a hose. Could it be leftover fuel or something?

What can I expect from a full service by a mechanic (Dirt Bike)?

Just out of interest, what should I expect a licenced mechanic to do in a full service to a dirt bike?

Bike: 2013 Honda CRF150RB 4 stroke

If you're creepy and have taken your bike to the same place as me before: I took it to RPM motorcycle Services.

What I'm hoping they'll do: Apart from things like the filters, oil levels, lubricants, etc. I'm hoping they'll get round to making sure the valves are right. Maybe it's just in my head, but I reckon the bike's lost a bit of power since I first got it.

Time since last service: 20-35 hours (I know, It's overdue)

Not expecting them to do this, but hey: Jetting?

Jee, this is getting way too long
Thank's in advance for any answers! -Harper

Good first motorcycle?

I'm looking to get my first motorcycle. I took and passed the MSF course, riding the Suzuki TU250X. Before the class, I had never sat on a motorcycle, so almost no experience. I'm looking for 70's/80's UJM. I like the look of the Honda Nighthawks or the Suzuki CB's, but I'm open to whatever. I'm 6' 3" 235lbs 36" inseam so I want something I can comfortably ride and not look like a bear on a unicycle. Obviously, I want decent reliability (although I realize anything that old will have problems), but I have no problem adjusting valves, cleaning carbs, etc. It would be a commuter first and a toy on weekends. I live in the middle of nowhere, so my commute in 1/2 hour on empty highways. What makes/models would be best in your opinion? What engine size? Anything to avoid?

Added (1). I'm not dead set against cruisers, but I prefer a sportier look.

Added (2). Suzuki GS not CB

Which is a better deal for first motorcycle?

Which motorcycle is a better deal in your opinion?
I'll convert these numbers to USD$, i'm from another country so prices may be higher than usual US prices, this is my first motorcycle mainly for commuting to and from work, will be using for 1+ year then reselling and upgrading, I will be paying through finance, all are from dealerships.

1) 2012 kawasaki ninja 650R, 12000 km milage, 4300$ USD
2) 2014 kawasaki ninja 300, 10000km milage, 3750$ USD
3) 2015 Yamaha R3, 1000km milage, 4500$ USD
4) 2015 Honda CBR 300, 5000km milage, 3450$ USD

For comparison purposes a 2016 ninja 300 new is around 5000$ USD here
Thanks for the help and any other advice is well appreciated!

Added (1). Just saw another bike: KTM RC 390, 4500km milage, 3850$ USD

Honda CX500 dies while riding with a full tank of gas

I have a 1982 Honda CX500 with 53,000 miles on it, yes its a lot of miles but the bike is in amazing condition. Ok, now dropping the sales pitch, yesterday and a few days ago i was out riding and my bike started to lose power in fifth gear at 55 mph. I shifted down to fourth gear and it continued to lose its power till it just died forcing me to pull the clutch and use my momentum to ride to the side of the road. Now i have a full tank of gas, and the fuel valve is pointing at the on position, not res. After a few minutes of pushing the start button and pulling the choke in and out it starts back up and rides fine for the rest of the day. What can i do and start checking? I'm a car mechanic so i know my way around an engine.

Tough MotorCycle Break In Process?

I just bought a brand new 2016 Honda CBR500R fresh out of the crate, i'm close to 500km and I have been riding it pretty hard (full throttle, improper gear shifting like from 5-1 without releasing the clutch, shifted without the clutch a couple of times, and sometimes not letting the bike warm up before riding), I just figured out about the break in process and the oil change at 1000km, i'm scared this might cause some damage to the bike and how long it will last. I have noticed the shifting getting soft to where I can't feel shifts, and the braking has softened up a lot as well. I figured the engines would be tested in the factory and alreading broken in but i'm and idiot.

Added (1). What happens to an improper motorcycle break in?

Added (2). What happens to an improper motorcycle break in?