Back brake will not bleed - 2000 Cagiva Raptor 1000

use a vacuum pump, have someone keep brake fluid full, do not it go low or you will introduce air back into system,
look online for bleeding brakes using hose and jar and brake fluid. either of them is easy. HF also sells his item.

Amazon com MV8000 Automotive Tune up and Brake Bleeding Kit Automotive

Make sure master is full, maybe over fill new brake fluid. Find a helper to push on the brake pedal. You loosen the bleed screw (looks a little like a grease fitting with a hole in it) on the back side of the wheel until there is no more air. tighten. Refill Master cylinder. Then other side same process. Do several times. try to collect the "used" brake fluid to prevent a mess. Now do the same for the front to make sure they don't have any air. IF it still is a soft pedal better have reliable brake shop check.

Air in line need to bleed out air

Might be a leak somewhere in brake lines. Or some gasket gone bad in brakes (then there is probably a leak as well). If no leak then I assume there is some air in the brake system, sounds like in lines which lead to back brakes so I suggest you bleed back brakes (preferably bleed the whole brake system). In my car (not bolero though) there is some kind of braking power balancing system with extra bleeding screw at the back and this could have air in too. You can find further information how to bleed braking system from your car manual or generally from the Internet. Usual drill is to bleed the furthest brake first then continue until closest brake to your car brake fluid reservoir.
PS: If your brake pedal feels soft and get harder by each push then there is definitely air in the system. If it stays soft you might have a leak.

Bleed the back brakes first until you get clear brake fluid then you bleed the front brakes, make sure you keep the brake master cylinder topped up so you don't get air into the brake lines..

take the cap off of your master cylinder fill and open the bleeders on the back brakes and let them gravity bleed

If your doing a one man brake bleed, you would have a tube attached to the bleeder valve,
the other end submerged in brake fluid, so when your pumping the brakes to bleed the air
bubbles out, no air can go back into the brake system. good luck!

Hi to bleed the brakes you need to do the following.

1 make sure fluid is topped up all the way
2, then start with one brake and undo the bleed screw use a container to catch any fluid that will come out, now with the bleed screw undone get someone to push the brake pedal down to the floor and hold it on the floor.
3 do bleed screw back up then get the person to pull the brake pedal back up it may be stiff but if you get your foot under you should be able to do it.
4 then once pedal is up undo bleed screw,
5 push pedal down
6 do bleed screw back up
7 pull pedal up
keep repeating that until all the air has stopped coming out, but make sure you keep an eye on the fluid level dont let it get low as you will have to bleed the whole system again

make sure you do the bleed screw up before pulling the brake pedal back up if you dont you will just be sucking air back into the system.

let me know how you get on or if you need further assistance ok

plz rate this solution as i have a whole page of unrated posts, thanks

Dakota, 2001-2005

Bleeding the Brake System
Brake fluid tends to darken over time. This does not necessarily indicate contamination. Examine fluid closely for foreign matter.
The primary and secondary hydraulic brake systems are separate and are bled independently. During the bleeding operation, do not allow the reservoir to run dry. Keep the master cylinder reservoir filled with brake fluid. Never use brake fluid that has been drained from the hydraulic system, no matter how clean it seems.

1. Clean all dirt from around the master cylinder fill cap, remove the cap and fill the master cylinder with brake fluid until the level is within 1 / 4 in. (6mm) of the top edge of the reservoir.
2. Clean the bleeder screws at all 4 wheels. The bleeder screws are located on the back of the brake backing plate (drum brakes) and on the top of the brake calipers (disc brakes).
3. Bleeder screws should be protected with rubber caps. If they are missing, the orifice may easily become clogged with road dirt. If the screw refuses to bleed when loosened, remove it and blow clear. Aftermarket caps are readily available.

Bleeding the ABS System
This is accomplished using the same methods as for the base brake system. Refer to those procedures.
ABS system bleeding requires conventional bleeding methods plus use of the DRB scan tool. The procedure involves performing a base brake bleeding, followed by use of the scan tool to cycle and bleed the HCU pump and solenoids. A second base brake bleeding procedure is then required to remove any air remaining in the system.

1. Perform base brake bleeding. Refer to the appropriate section.
2. Connect the scan tool to the data link connector beneath the dashboard.
3. Select "Antilock Brakes" followed by "Miscellaneous", then "Bleed Brakes". Follow the instructions displayed until the unit displays "Test Complete", then disconnect the scan tool and proceed.
4. Perform a base brake bleeding a second time.
5. Top up the master cylinder.

Hope helps (remember rated and comment this).

This is because you need to bleed the back brake system
it doesn't take long to do. This is a detailed guide on how to bleed brakes front and back
http://www.webbikeworld.com/Motorcycle-technical-articles/bleeding-motorcycle-brakes/bleeding-motorcycle-brakes.htm