1984 Kawasaki GPz 750 not starting immediately

[N00dle]

Hey there, guys!

So I just bought a bike to replace my 84 Honda Magna. A 84 Kawasaki GPz 750 (ZX750).

It runs great, but it doesn't start immediately. It does start, without fail, but it takes a lot of just holding down the engine start button and I don't think that's healthy. Also, it killed my battery when I ran out of gas and had to keep turning the engine to get the fuel through the pipes again.
Why does it do that? Is it a starter issue? Carbs maybe? I do know that the carbs need to be cleaned. It bogs down at high speed, until you open the clutch, then it rockets off again.
Also, a warning light keeps blinking on the dash. I've read that it might be because it's not a factory battery, but I found that on a 750 Turbo forum, so I don't know if it applies.

Thanks for always helping a young biker out!

[Johnj]

Try a can of Seafoam®. Mixing instructions are on the can. Buy a plastic baby bottle that is marked in fluid ounces and milliliters. I would change the oil and oil filter. I would change the fuel filter. I would check both sprockets and the chain. Have you bought a book for it yet?

[BRUMBEAR]

SEAFOAM is the nectar of heaven!!!!

[N00dle]

I found a manual for the Turbo model. I don't know how many differences there are, apart from the turbo. Do any of you know?

[BRUMBEAR]

a semi plugged exhaust may give you some problems or an air leak both would give a warning light if machine is equipt.

[Johnj]

What is this light you speak of? Is it on the face of one of the instruments or is it in a little stack of around 4 or 5 lights between them? Is it marked? Kawasaki`s from that time had a red light on the dash that would light up every time you used the brakes.

[N00dle]

Here are a couple of pictures of the control area.
At the top we have the warning light. It flickers in time with the low fuel light, which flickers regardless of the amount of fuel in the tank, so that's broken for now. I'm hoping that the warning light is just a warning that I'm low on fuel, even though I'm not. Does that sound plausible? Because if that's the answer, I just need to fix the gas gauge, which is surely cheaper than a mechanical problem.