Hi guys, bought a second hand good looking 2015 plate Lexmoto Adrenaline as my first commuter.

Please accept my apologies in advance if I ask something that perhaps I should know, but i'm afraid my knowledge is limited.

I'm a large chap, 6'4" and 130kg, i'm already aware of my size, and the last forum I joined gave me nothing but stick saying a 125 would never do me justice, went straight to 'do DAS and get a bigger bike blah blah blah'.

That being said, i've dropped 6kg and am still losing weight so that will help me.

OK, moving on, the bike came with 1400km on the clock. All good and well I thought. Bike was remarkably clean in appearance anyway.

Noticed a couple of things (i've only had the bike since Saturday 14th):

The gears feel clunky shifting up and down. Experience on fluid shifting needed? If so, what RPM should I be changing gear at? Or do I need to watch out for something else that will smooth this out?
Speedo is saying i'm doing a speed I KNOW i'm not doing. There is no way I'm doing 50-60mph on this bike when cars are overtaking me shaking their heads on normal suburban roads. Couple of colleagues have said i'm doing 20mph when speedo says i'm doing 30mph.
Due to my size, I would like to change the suspension on the rear a little to accommodate my weight. How do I set it correctly?
Bike does NOT start first time without choke being on. Idles at 4k revs with choke on and about 1.5k revs without.
How the heck do I know i'm about to run out of petrol?
I hear a constant rattle which is actually very regular, like a fast ticking clock. It annoys me. I would like to make that go away. Sound comes from the front and usually starts when i'm going fast enough to be in 4th/5th gear.
I'd like to get a bit more beef out of this bike, it's rated to 8.4kw, how do I get the 11kw and keep it legal?

How often do you guys service your bikes? Do you do it yourselves or take it to a mechanico?

Thank you for reading my first thread, and thanks in advance for taking the time to answer!

Kindest regards

insomnai