I made my own pressure-bleeder cap and system for my vehicles. I never thought to do it for the bikes. Might do that this weekend.

 

The port in the clutch master is blocked unless the lever is at least partially pulled in. It will not bleed in reverse with the lever at rest.

 

Something's not right. All I do is reverse bleed when I put new lines on and never touch the lever.

The return port should be open with the lever fully out, or how else would the compressed fluid return to the master cylinder under normal use?

 

The return is open until the piston gets to the fully retracted position.

 

I'm not understanding. How does the piston compress and move the fluid down the line if the return is open?
The return is only open when the lever is all the way out (at rest).. The piston blocks the return hole when you grab the lever and pull it towards the bar.

Regardless of what people think, if you've ever done the syringe method, the first thing you figure out is if you don't have the master cylinder cover on DO NOT to go pressing the syringe plunger super hard or else you will literally shoot brake fluid on to the ceiling of your garage and all over your bike.

 

According to this, partially pulling the lever blocks the port.

 

I can't speak to the science of it, LOL. I just know that on my RGS, the only way I can get it to work is to tie the lever ever-so-slightly engaged. Right or wrong, my presumption has been that something is blocked when the lever is at rest. <shrugs>

 

I don't see where in the 4 steps listed that it says that this is done to unblock the fluid. When a master cylinder is in it's normal released position, fluid is allowed to return to the master cylinder. Otherwise when the fluid expands from heat, or wear in the clutch which pushed fluid upstream, it would cause the clutch to be at least partially disengaged. That's why they tell you to not overfill or top off the clutch system with fluid as the level will rise as the clutch wears.

I believe what you are referring to in the diagram is part of the steps to remove the clutch release bearing and pushrod without affecting the slave cylinder. When the level is pulled in slightly the gravity of the brake fluid is prevented from pushing the slave cylinder out. If fluid could return to the clutch master cylinder with the lever pulled in, the clutch would not stay disengaged because the fluid pressure would be lost as it returned to the master cylinder.

I flushed the clutch brake fluid on my 2018 RG using the old fashion method and had no problem. I used a large syringe to remove the old fluid from the master cylinder and then bled until the fluid was clean coming out of the slave cylinder. I know others who have used a Mityvac to pull the fluid from the master cylinder through the slave cylinder into a trap contained. Same with the front and rear brakes. Either method should work fine.


Paul

 

Correct. If you go back to post #16, you will see I was quoting post #12. The reason for blocking the port in that procedure is to prevent the piston in the secondary actuator from moving towards the released position when installing the release bearing plate and retaining ring. Without blocking the port, it would be extremely difficult, if not impossible to install the retaining ring.

 

Yeah, reading is fundamental! I missed how you were pointing that out from the previous post.

thanks,
Paul