Bleeding Clutch

[james 1956]

I've rebuilt the master and slave cylinder and am having trouble getting the air out. I blew out the fluid lines and tried refilling them.

The clutch lever only puts out a very small amount of fluid any ideas?

[sfcrader]

When I did mine, I read somewhere to have the cover off and very slowly move the clutch lever and you will see small bubbles. Keep doing this takes about 15 mins. When no more bubbles are visible, replace cover and bleed as normal. Worked great for me. Hope this helps

[Marcarl]

As you move the lever with the cover off, take the handle of a screw driver and lightly tap the hose connection end of the cylinder. There is air trapped at that end and you need to get that out. It also helps to turn the handle bars to the right so that the MC is in the highest position.

[M61A1MECH]

I have also taken the lever and tied it back and tapped on the entire line as far as I could trace it back, also have left the handle tied back overnight to allow for the time it may take for small bubbles to work thier way out, then tapped some more.

Cover any paint or plastic in the process to help kep the fluid from spilling on any surfaces.

[Flyinfool]

I used a vacuum bleeder from Harbor freight to get it started.

 

IF you have speed bleeders installed the vacuum pump is the only way to get it started. Or you can put a stock bleeder back in to get it close.

[ragtop69gs]

 

All of the above are good suggestions. I have found the vacuum pump to be the best method along with tickling the clutch lever to release the micro bubbles trapped in the top.

[almariders]

Just changed clutch fluid a few days ago could not get the air out of the lines till I got a vacuum pump half price from Harbor Freight @25. Works like magic it will blow the air out of the system

[ragtop69gs]

Just changed clutch fluid a few days ago could not get the air out of the lines till I got a vacuum pump half price from Harbor Freight @25. Works like magic it will blow the air out of the system

 

Don't mean to get technical on ya BUT,,, vacuum pumps SUCK

[videoarizona]

Jeff, where do you dispose of old brake fluid? Guess I can call AutoZone or an automotive store...

[Flyinfool]

I put it in an empty brake fluid bottle and when the city has one of their hazardous waste collections I give it to them.

 

The city has these collections 2 or 3 times a year to help discourage illegal or improper dumping. At least I know it is being handled properly.

[Condor]

When trying to bleed a clutch that is completely empty of fluid on a Venture, it’s very difficult…maybe impossible… to get all the air purged out of the lines normally because of the relation of the reserve to the slave. Unlike bleeding the brakes where the pressure is built up by rapid pumping the pedal or lever, the clutch does not build pressure. Squeezing the clutch lever has to be done slowly and constantly. Using this method causes the air bubbles in the lines to move down toward the slave with each stroke. During the release of the lever the air bubble rises upward in the line. Air rises. So in effect you end up with these bubbles rising and falling and going nowhere. I've seen threads over the years where the owner has struggled for days to get the clutch properly bled.

 

Reverse bleeding is done by forcing DOT fluid into the slave bleeder valve and forcing the air up the line and into the reserve. This can be done several ways. If you have a Speed-Bleeder installed it will have to be removed. If you have a regular bleeder, the reverse bleed can be done with the valve in and open, or you can remove the valve like a speed-bleeder. I find the removal of the valve the easiest.

 

Take a rubber ear wax remover blub that you can find in your local drug store and snip the tip off a little bit at a time until it fits into the threads of the removed valve. It should fit snuggly and the opening should be a bit off the bottom of the hole in the slave.

 

Remove all the fluid in the reserve.

 

Suck up enough fluid to fill the bulb, insert it in the threads of the slave and force the fluid into the slave. Keep an eye on the reserve to make sure it doesn’t overflow. Not good. Sometimes you can hear bubbles as they make their way out of the line and into the reserve. If the bulb runs out of fluid it can be reloaded. The hole can be blocked off with your finger while refilling. When no more bubbles appear stick the bleeder valve back into the slave, adjust the level of the fluid in the reserve to about half full, replace the reserve top and you’re good to go.

 

This whole process can be done in about 15 minutes. When done, go for a ride.

 

PS: After first opening up the reserve, lightly squeeze the clutch lever a tad. The surface of the fluid in the reserve should deform slightly. Squeeze hard and you’ll end up with fluid on you and the bike. Not good. What this shows you is that the expansion orifice is clear and functioning. If it’s plugged the hot expanded fluid will have no place to go, and start to push on the slave as if you were actually pulling the lever. The clutch will start to slip. This is also why the reserve should be only filled half way. I have seen owners spend a lot of money rebuilding their clutches, and all they had was a plugged expansion hole.

 

Hope this helps