XM-2000 front brake adjustment - mine squeaks, gets hot and eats range

It's disk brakes? Likely the pads are rubbing too tightly.

The pads are probably sticking and the return spring isn't strong enough to return them to the open position. I don't have the brake assembly in front of me so I can't tell you how to address it off the top of my head. I can look later and send you the info - or you can google for an answer.

There are no return springs in disk brakes. There is always pressure of the pads
against the rotor. However, it should not be a lot. Should not cause heating or
put so much pressure on the rotor that the wheel does not rotate smoothly with
just a little drag. I have worked on several scooters for this same problem
and have not really found a good solution.

The main thing I do is disassemble the wheel and caliper. make sure the caliper
pins are lubed to allow the floating part of the caliper to freely move. This
was designed to allow for wear of the pads. Sometimes, if dry, the assembly will
not float so will bind putting too much pressure on the rotor.

Also make sure pads are clean and have not picked up any dirt or grease on the surface.
This results in binding of the rotor.

Make sure that when you tighten the caliper mounting bolts that they don't cause the
assembly to tweak out of alignment with the rotor.

I have a Zapino so do not know if the brakes are the same manufacturer.
All the fluid leaked out of my front brake so I will be disassembling
the caliper to investigate. I suspect in your case there is a valve that
should allow fluid pressure to back off when you release the brake lever.
This would back off the pressure of the pistons against the outer pad.
Seems that a complete disassembly would be in required to inspect all
the parts. Could be some debris was allowed into the system during manufacture.
It is a closed system, unless you take off the Master cap to add fluid.

Hydraulic brakes are all the same. You have a closed system except at the Master cylinder where
the cap is to add regular brake fluid. When done, it does require bleeding the air out of the system.
The master cylinder is on the handlebars, the slave is the caliper. Yes, it is messy. If you decide
to take it apart, the best cleaning solution to use is brake fluid. Flush the master, the hose and
the caliper. Reassemble and add fluid. Some folks use a pressure device to add fluid from the bottom
and it pushes air out the master. The other way is fill the master, pump the brake lever, open the
bleed fitting at the caliper and shut it quickly. Do this until nothing but fluid comes out. Brake
fluid comes is several DOT versions and regular fluid or synthetic fluid. We don't know what China
is using. I plan on flushing everything with DOT 4 or 5 and then filling with same.
My scooter repair is planned for Thursday. I will be taking pictures.

There are two kinds of brake fluid. Mineral based and Synthetic. There are various DOT ratings.
I am not an expert on the differences. I just use what the manufacturer recommends. For some
types of rubber products in the brake system, you cannot upgrade from mineral to synthetic. The
rubber would be damaged. So anyone thinking it would be great to go synthetic, just check with
the manufacturer first.

Regular Brake fluid (not synthetic) starts absorbing moisture as soon as you open the container.
Therefore to minimize moisture in the brake system which leads to rust, they recommend you get a
brand new can or bottle and only when you are ready to take the cap off the master cylinder,
open the container to add the fluid. Of course this means that once opened, you are not supposed
to put the cap back on the can/bottle and save it to use weeks, months, years later.
This is for the mineral based brake fluid.

I think you have confused synthetic with silicone brake fluid. I use Valvoline synthetic brake fluid in all my vehicles. Most brake fluid is glycol not mineral oil based. For more information about brake fluid check out the link below.

http://www.motorcycleproject.com/motorcycle/text/cows-brakefluid.html

Philip

That is a very good article on Brake Fluids. Yes, Silicone is what I referred to as Synthetic.
Glycol is what I refrred to as Mineral Based.
Here is something from Wikipedia:

Mineral-based
Alkyl ester
Aliphatic amine
Diethylene glycol
Diethylene glycol monoethyl ether
Diethylene glycol monomethyl ether
Dimethyl dipropylene glycol
Polyethylene glycol monobutyl ether
Polyethylene glycol monomethyl ether
Polyethylene oxide
Triethylene glycol monobutyl ether
Triethylene glycol monoethyl ether
Triethylene glycol monomethyl ether

[edit] Silicone-based
Di-2-ethylhexyl sebacate
Dimethyl polysiloxane
Tributyl phosphate

Took my brakes apart at the wheel. Some pictures here: 1st two from a spare brake asm.
Master Cylinder on the handlebar

Caliper Assembly (electrical tape is holding a spacer between the brake pads).

Here is the Leaking Caliper. Leakage seems to be from the seals, there are two for each piston.

Normally, disk brake pads should not touch the disk when not being used.

When properly designed and built, and operating properly, the piston has a special flexible gasket around it that keeps the brake fluid from coming out. The outer surface of this gasket resists going out, and the cross section of the gasket deforms (stretches) slightly as the inner surface of the gasket is carried toward the disk by the piston.
As the hydraulic pressure behind the piston is reduced, the stretched gasket's cross section attempts to return to its un-distorted shape, pulling the piston back in just a little, which takes the brake pad off the disk.

As the pad wears, the "resting" position of the gasket will gradually move outward, automatically "adjusting" the disk brakes.

If the piston and cylinder are not perpendicular to the brake disk, or the pad wears into a wedge shape, or the pad is too thick, or the gasket and cylinder walls are not in good shape, this auto-adjusting might not happen properly, and the pads may drag, which is NOT good, desired, or normal, in spite of what a dealer or some service people will tell you.