Hi, everybody! My 86 has 70k on it. About 10k ago, I installed a new clutch for no particular reason other than I didn't know if it had ever been done. I haven't had a problem at all. The bike has sat since last September. A month ago, I started it up and let it get warm. I went to put it in gear, and the clutch lever had NO hydraulic pressure, only spring tension. It feels like the lever was pulled in, and the pressure stayed. Now, I'm afraid to try to put it in gear for fear that pulling in the lever won't do anything to disengage the clutch. Really need some help with this one...
Clutch lever has no hydraulic pressure
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The Beekeeper
Well-Known Member
Is the resivour empty?......Any leaks?......You may need to rebuild the master and slave, You could fill the master and gently clamp the hose just beyond the banjo fitting, loosen the fitting and bleed the master there, with the hose clamped you should have a rock hard lever if bled properly, move on to bleeding the slave afterward...........................Tom.
blaxmax
Well-Known Member
Mity Vac to the rescue----
http://www.ebay.com/itm/Mity-Vac-Va...hash=item4187809a32&item=281446226482&vxp=mtr
http://www.ebay.com/itm/Mity-Vac-Va...hash=item4187809a32&item=281446226482&vxp=mtr
Using a large syringe to push fluid up towards the master cyl from the opened slave cyl bleeder valve is what many members do to solve this issue. You have to monitor the amount of fluid in the master cyl as it can become "my cup runneth over" if you don't empty it as you push the syringe plunger to introduce brake fluid into the slave cyl bleeder valve.
For me this works better than my Mityvac when you pull fluid towards the slave cyl. In that case you normally have to add brake fluid to the clutch master cyl.
Using the syringe method, once you no longer see any bubbles coming out of the two differently sized (one much larger than the other, the one closest to the master cyl banjo bolt is the smallest, and may need to be kept open by the use of a sewing needle to probe it) holes in the floor of the master cyl, you should be able to close the slave cyl bleeder valve, and then repeatedly 'fan' (rapidly squeeze and release) the clutch lever, and get a normal clutch resistance very quickly.
Some members choose to use an additional step once the above results in the evacuation of the air in the system. They use some sort of method to hold the clutch lever to the handlebar (for a prolonged period of time, as in overnight) in the belief this allows a migration of any residual air in the system to exit to the master cyl reservoir. I have never used this step, as once I get a return of normal clutch lever resistance where the clutch pressure plate is released, unless you have a bad leak at either the master cyl plunger or the slave cyl, your air should have been expelled by the syringe method. But, if you try the overnight clutch lever to the handlebar method once your bleeding results in a firm lever and total clutch disengagement, it won't hurt anything.
For me this works better than my Mityvac when you pull fluid towards the slave cyl. In that case you normally have to add brake fluid to the clutch master cyl.
Using the syringe method, once you no longer see any bubbles coming out of the two differently sized (one much larger than the other, the one closest to the master cyl banjo bolt is the smallest, and may need to be kept open by the use of a sewing needle to probe it) holes in the floor of the master cyl, you should be able to close the slave cyl bleeder valve, and then repeatedly 'fan' (rapidly squeeze and release) the clutch lever, and get a normal clutch resistance very quickly.
Some members choose to use an additional step once the above results in the evacuation of the air in the system. They use some sort of method to hold the clutch lever to the handlebar (for a prolonged period of time, as in overnight) in the belief this allows a migration of any residual air in the system to exit to the master cyl reservoir. I have never used this step, as once I get a return of normal clutch lever resistance where the clutch pressure plate is released, unless you have a bad leak at either the master cyl plunger or the slave cyl, your air should have been expelled by the syringe method. But, if you try the overnight clutch lever to the handlebar method once your bleeding results in a firm lever and total clutch disengagement, it won't hurt anything.
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Holding a clutch or brake lever under pressure overnight to allow air to migrate back up & out of the system is a myth. The only air that has access to the fluid intake hole at the bottom of a master cylinder (when it's lever is compressed) is air that is already outside of the brake/clutch lines and sitting inside the master cylinder on THIS SIDE of it's working piston & seals.
Rather, I suspect what is happening for the folks who use this method and say it works is this: Air under pressure breaks down into much smaller atoms and blends back in (temporarily) to the brake fluid around it. After that constant pressure is removed, the occasional lever action might serve to keep that air in suspension, but sooner or later, when the bike sits for an extended period of time, those tiny air molecules will once again begin their trek upward and re-collect into a larger bubble to give grief all over again.
I'm no brake fluid scientist, but that's my unedumacated theory, and I'm sticking with it, because trapped air isn't going to magically disappear under constant lever pressure, and also, once that lever is applied, no air will have access for it's escape through the top....if it did, our brake/clutch systems wouldn't work at all.
Rather, I suspect what is happening for the folks who use this method and say it works is this: Air under pressure breaks down into much smaller atoms and blends back in (temporarily) to the brake fluid around it. After that constant pressure is removed, the occasional lever action might serve to keep that air in suspension, but sooner or later, when the bike sits for an extended period of time, those tiny air molecules will once again begin their trek upward and re-collect into a larger bubble to give grief all over again.
I'm no brake fluid scientist, but that's my unedumacated theory, and I'm sticking with it, because trapped air isn't going to magically disappear under constant lever pressure, and also, once that lever is applied, no air will have access for it's escape through the top....if it did, our brake/clutch systems wouldn't work at all.
I'm happy to report, PROBLEM SOLVED!!! Thank you again, everyone!! I tried bleeding the system at the slave, but no air ever came out. But with the reservoir cap off, I could see a couple of extremely small bubbles every several seconds. So I began working the clutch lever in and out about 200 times. More and more bubbles began coming up until finally, it was only fluid. Thank you again for all of your input, this forum never disappoints!!
sdt354
Well-Known Member
Just semi-related, but I'm going on a few months with Dot 5 brake fluid in my rear brakes. I'm thinking it was a success. I'm not sure if the alcohol flush was necessary, but I did that first and bled the system until a nice stream of purple fluid came out. My clutch and front brakes are next when I change out my masters to FJR's.
+1 for the Mighty Vac. It's worth owning for it's many uses. But the upstream syringe method is gaining popularity here. And sounds like the way to go if you don't have the Mighty Vac. Lots of treads and methods here on the forum.
+1 for the Mighty Vac. It's worth owning for it's many uses. But the upstream syringe method is gaining popularity here. And sounds like the way to go if you don't have the Mighty Vac. Lots of treads and methods here on the forum.
I have 3 different Mityvac's and while the oldest still works, it's a bit sticky. I rebuilt it once. The second is the high-zoot, analog vacuum gauge model. The third I have is a NIB off the tool truck, special price, gotta have a backup!
I like the mityvac for the brakes and the syringe for the clutch.
I like the mityvac for the brakes and the syringe for the clutch.
