Rear brake bleeding motorcycle YZF R1?

** dude ,CRS (cant remember S**T) - **I forgot to mention, you should take your caliper off and clamp the piston shut because you can have air trapped in your caliper and all the bleeding in the world wont get it out unless the piston is fully depressed dude..peace and hope this is the root prob thats got ya chase'n ya tail like i did also B4 brother*** Peace man-wallyB

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1st-If you can,, try raising just the front end of the R1 up,so the damn near arched up in the middle -un level flex hose running along the rear swing arm to the caliper is more at a better top to bottom bleed angle,try pivoting the lil Fluid bucket if it has the short flex line between it and the actual rear master..if its even this type or likely possible to not let the extreme angle let the fluid that's sideways in the fluids upper lower area not let air keep re entering to infinity and beyond eating up our valuable jobber quote time........ a good tech like you and me ever really care to go down that road!..

( i feel ya pains brother,, and way back you had advised me on my Isuzu Tranny,..PS,yep it was internal likely bleed seepage..pressure bleed off ,inner workings as you stated..so its on the ground and a new ones in her now ,,gracious amigo,,because you knew and took time to offer what you would have done ,,i saved alot of un needed wasted energy and busted knuckles!! )

be damn sure not to overlook that someone Before you hasn't moved/adjusted the plunger arm , the foot pedal , and the master ..(if it is of the adjustable type that's threaded with a lock nut .. so it increases or decreases the amt of travel from the foot brake,if someone has altered this due to severe pad loss from wear and / or also a bit of pad wore down the rear rotor/disk too,with new pads it ain't gonna do the trick no more because it is not within the normal throw movement it needs to be to get it to bleed or work correctly

and a rumor- did you ever hear of un mounting the caliper and stuffing an old pad between the two new pads,and with it in an upside down position or on its side, it can allow the bleed process to work..never been this route B4,but a Yamaha tech i respect that's also hands on and not only book guide smart had mentioned this trial and error tip.

.and if the banjo washers seeped air and not fluid as above mentioned,and i have seen it personally on a Fireblade 929RR before,...with that particular condition and on that Honda....they would still pump up to near full lever,but would remained spongy instead of firm and after letting it settle for a few minutes,..it would have to be pumped to get any action out of it..and that did not go away with a new master rear either,it was trapped air in the remaining part o the system in that case...

big Hint..these rears are sensitive to to little or a little to far travel while bench bleed or etc= no go.These can so easily be pushed a hair to far while benching to trap air in the master plunger that wont bleed out under normal pedal travel..

Backwards fill is preferred as the easy way out on these,some few others, and all the Polaris Victory street and most all their atv line up too.

I reckon the master cylinder is not making pressure. The MC is pushing enough oil to bleed the lines but once the nipple is closed, the seals leak like mad and the piston does nothing.

You can check the caliper by hooking it up to a different bike. Don't need to mount anything, you just need a hydraulic pump of some kind.Put some 4mm steel in between the pads if possible.

R1 Master Cylinder

If you took loose the banjo bolts you MUST replace the crush washers. Ive seen it time and time again, it might not leak fluid from them but they will suck in air. Lastly try angling the caliper and bleeding in a sequence..remembering air rises.

If you have a mighty-vac you can always bleed it in reverse by putting pressure to the caliper from the mighty vac and have the hose running to brake fluid...Ive done it a few times on extremely tricky master cylinders but that was a last resort and its easy to spray brake fluid every where if your not careful

Brake dust gets embedded in the brake shoes. The brake shoes get glazed. That's most likely the problem. Remove the rear wheel. Clean the shoes and brake drum with "contact/brake" cleaner (available at auto parts and bike shops). Careful not to breath in the brake dust (harmful). Either change the brake shoes, or score them up with a wire brush.

I used a http://www.speedbleeder.com/ on the front of the Savage -- easy!!