The reservoir for the front brake is on the master cylinder on the right handlebar. The reservoir for the rear brake will be on the frame behind the right foot peg.
Yes, It will leak oil. How much will depend where the hole is. When the engine is running the oil is a pressurised system so it won't be supplying enough oil the the moving parts of the engine.
Take a photo with your phone and there is a button on the bottom of the comment box. Use that to add photos.
As a general rule If the cylinder head has ANY damage like holes and cracks Replace it. A cylinder head is cheaper than a replacement engine or a bike.
No, use whatever they recommend. Using wrong lubricants can ruin engines. As I said last night, this is not a well know motorcycle. It is a Honda 90 clone.
That is about right for a 110cc step-through scooter. They are very unaerodynamic. For a small engine it also depends on your weight and how much of a sail (wind resistance) you present to the oncoming air.
https://www.google.com/search?q=vuka+xl110+specs
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This is a short, it could be the wire from the fuse chafing on the frame, follow it thru to the wiring loom, failing that then look at all te wiring for a split or exposed wire.
I take help from online websites that have this service like helping in repair some like reliable-store have instant help.. others are a bit slow which I don't prefer... rest is up to u.. U can also get free manual works fine .