Haven’t ridden the bike in a few months. Battery tender had come unplugged so battery was dead but charged quickly when I plugged it back in. I jumped on to go for a quick jaunt...I pulled the clutch in and the lever went straight to the bar, no resistance at all...never had this happen. I have clear tubing and I could see a few small air bubbles in it just outside the reservoir.

Questions are..

I assume this happened because there is air in the line?

How did air get in the line?

Best way to resolve this issue?

Limited mechanical skills :)

Thanks in advance....

Troy

If you see the bubbles in the tube to the reservoir, chances are you also have some in the master cylinder and that is the reason the lever has no pressure. You should try opening the reservoir and working the clutch lever. Tap on the MC and the rubber tube. That might dislodge the air and it will float up to the reservoir and out into the air in your garage and your done. Worth a try. If it doesn't work after repeated attempts, do steps 44 through 54 here. You might want to read the whole tutorial but all bleeding is pretty much the same no matter what location the bleeder is.

http://zx14ninjaforum.com/messages.cfm?threadid=EF69194F-1372-66AE-3B981C05AA26103E

Perfect time to practice. You can't literally screw it up any more than it is. If you let air in, there already is air in there. Just observe, bleeder CLOSED, PULL lever PUMP-PRESSURE in lever-PULL HOLD, OPEN bleed-fluid moves, CLOSE bleed, RELEASE lever PUMP-PRESSURE- HOLD, OPEN bleed....and just keep doing it until fluid flows along with your air bubbles. Just don't crank on those bleeders when you close them. IT's not necesary and just wears out the threads, Barely snug is fine.

Master cylinders with air are a bitch to get flowing. Be persistent. It will be difficult to know if you are doing the bleed correctly because it will not be real obvious when you get a tiny bit more pressure pumping. There's air in there. Keep at the pump hold open routine and it will eventually start to flow.

If when you get the MC clear of air the lever is still soft, continue with the tutorial and bleed the slave.

I would normally start with the slave and then do the MC but if you have no pressure in the MC, you can't do either.

Go back and bleed the MC one more time after the slave.

Don't tighten down those bleeders until you are done. finger tight is fine. Torque after finished. You will probably get seepage at the bleeders. Watch for this. Wash it off immediately. Give it a little crick more tighter on the bleeder. Just a touch. That should seal it. It will stop eventually. This is why I don't bleed unless I really need to and why I am so careful about not wearing the threads--the seepage. Sounds like you probably will need to bleed.

How did air get in the line?

Possible you have a loose banjo bolt, leakage at the slave cylinder seal???? A loose bleeder??? I would not bother to check torque unless you see signs of fluid leakage or if the problem returns after bleeding. No sense in over-tightening banjos or bleeders if they are not definitely leaking.

This will probably be totally fine after you get the MC bled.

OR get a Mightyvac. Mine is for shit but it seems like a lot of people like them.

Thanks Rook...was hoping for a plain English response and advice...will give it a try this weekend. Will let you know how it goes.

Sequence if I were to walk up to air in the master:
1. Squeeze the tube to expel the bubbles and shows all liquid throughout the tube.
2. Open the clutch master's bleeder nipple with a closed end 8mm wrench... but first...
3... Cover the nipple with a paper towel.
4. With the bleeder open, pull the lever to the grip and close the nipple before it gets to the grip.
5. Pump the lever no less than 5 strokes and wait at least 2-3 minutes.
6. Open nipple and pull the lever to the grip and close the nipple before the lever reaches the grip.
7. You should have a pedal.
8. Sight the level in the rez and top off if needed.
9. Read cap to know what fluid number is used, ie, dot 3 or 4.

Why close the bleeder before the lever contacts the grip, Hub? Why not use the full stroke to pull the fluid from the reservoir into the MC?

This has got me thinking why fluid pressure might be lost after winter storage. I guess because pressure wants to escape whatever it's contained in. If there is any little way out, pressure will slowly seep. There's lots of moving parts and seals in hydraulic cylinders including brake calipers that pressure might slowly squeeze past. If the path of least resistance is up, the fluid just forces its way up into the reservoir. Pump the lever a few times and the fluid that escaped is pumped back into the system and trapped behind the seals again. Pressure is restored.

If the path of least resistance is down, the fluid just leaks out. If there is zero pressure and the weakest link is down low away from the reservoir, I can see how vacuum might be caused if the temperature drop causes the fluid in there to contract. That might suck air in rather than suck fluid down from the reservoir. That air could very well rise to the MCand you got what tc has right now. Just a theory.

Reminds me, I really gotta change the rubber parts of my hydraulics some day. $$$ Ten years old!

Damn, tclogston, I am having the exact same issue today...!

There is also a thread at hayabusa.org about this problem with brakes right now.

* Last updated by: Rook on 4/6/2018 @ 6:32 PM *

Rook, your excellent brake and clutch bleeding tutorial worked perfectly for me, I can't thank you enough!

GREAT! Glad to help out.

Never had it happen to my brakes but twice I've had my clutch suck air over winter. I think it sucks air past the cup seal on the slave piston.

It's the for every action-reaction. Say the bubbles are sitting under the nipple opening. Say you purge the bubbles on the one stroke. Say if you closed when the lever hit the grip, here comes the reaction before you close the nipple. So by closing when the fluid is behind the bubbles, you are still pushing the fluid one way and won't give it time to neutralize and suck air back on the hold at the grip and then close. Make sense, Rook?

Yeah, I gotcha, Hub. Thanks for yet another tidbit of knowledge. I will try that soon. Replacing the rear brake MC. Going with external reservoir.