Bleeding Hydraulic Clutch

[riffer]

Okay, its my first day back at work today since Nicholas was born, and also the first day back on the bike since 21/2/05.

My nephew and nieces were around at home yesterday and the young boy was playing on my bike and I reckon he's been playing with the clutch lever while the bike was leaned over and now the clutch needs bleeding.

I reckon the fluid was a bit low and he pulled the lever while it was leaned over, letting some air in.

Symptoms: clutch does not start to disengage until half-way in, and engages almost immediately you release the lever. In fact, I've stalled it three times today already. Also, its bloody hard to change gears even with the level pulled all the way in. And, its hard to move the bike backwards with 1st engaged and the lever pulled all the way in.

I don't think it's wear all of a sudden so I'm thinking it's air in the line.

Having had cable clutches on all my other bikes I've not done a hydraulic one, but I'm fairly experienced with brake bleeding so I'm happy to give it a go.

Any ideas/helpful advice on bleeding Yamaha clutches that I might not know about? I guess the fluid's the same as brake fluid but I could be wrong...

[Blakamin]

may as well replace all the fluid... same bizzo as brakes as far as I know....

[vifferman]

It definitely sounds like your clutch needs bleeding. While it's basically the same as brakes, it's a little bit harder to do, as the master cylinder's often smaller, you can't build up as much pressure, and bubbles are harder to eliminate. Also, clutch cylinders are more prone to leaking without being noticed, and more likely to be neglected.
'Power bleeding' is easiest, but there are ways you can do it if you don't have a Mityvac or whatever.
One way to help get rid of bubbles is to turn the handlebars so the left bar is higher than the right, then tie it back with a cable tie, some string, etc., and leave it overnight. Tap any unions (like the one at the M/C) with a small spanner or screwdriver to encourage the bubbles to rise. Alternatively, you can loosen the unions slightly while the applying pressure at the lever, to allow a little fluid to leak out.
BE CAREFUL TO ENSURE THE FLUID DOESN'T GET ONTO ANY PAINTWORK!

[riffer]

BE CAREFUL TO ENSURE THE FLUID DOESN'T GET ONTO ANY PAINTWORK!

You've obviously never seen my bike Ian...

[John]

You've obviously never seen my bike Ian...

Thats so funny because I remebered you reffering to your profile picture and saying how its in such 'good' condition, and I had a chuckle when Mr Vifferman said that.

Although I didnt have the brawls to post saying so.

[riffer]

Love that Mr Oizo puppet Avatar John...

anyway, it must have been air in the fluid. Timothy and I have just returned from the gargre after bleeding the clutch.

Half a 300ml bottle of DOT4 later, we have clutch engagement at halfway out, and full takeup with just a bit to go. There's still a little bit of air in there, but I can't be arsed spending 4 hours and three bottles of DOT4 just to get rid of a tiny bit of air. I'll try again in the weekend.

So, I'm back in business now. And the bike even changes in to neutral when the motor's going now!

Yippee.....

[FROSTY:Me]

mate try the cable tie on the lever trick. --Ohh and the viffer has no clutch so Im gonna hata do the same job bugger it.

[riffer]

mate try the cable tie on the lever trick. --Ohh and the viffer has no clutch so Im gonna hata do the same job bugger it.

It's a piece of cake dude. Get Baby Bikie to help you by holding up the bottle the bled-off fluid goes in to.

It made Tim's day helping his dad with that one.

Oh, BTW, good windup on the cellphone the other day.

Fair put the wind up Gini's skirts, I tell you

[TonyB]

The slave cylinder isn't leaking is it? The one on my FZR does that, and I get the impression its a common fault.

[RiderInBlack]

"Roxanne" has a Hydrolic clutch lever. I had to replace her master cyclinder kit for it. Put the kit in the wrong way at first and wonder why it was not bleeding properly (it was sucking not blowing) Once I put the kit in the right way it was only just a bit harder to do than the brakes. This is how I go about it:
Once I have freash fluid in the whole line, I recycle the fluid back in the reservoir (using the same method of bleeding as in the brakes). I do this by having a bleeding hose long enough to go from the slave to the master (putting the end in the reservoir fluid). I keep recycling until I can not see any fine bubbles coming out of the hose.
By using this method I stop air being sucked back in the system, use less fluid, and can see when all the fine bubbles have come out. This eliminated power bleeding for me

[imdying]

I can't be arsed spending 4 hours and three bottles of DOT4 just to get rid of a tiny bit of air.

Since you've replaced all of the old fluid, you can just take the fluid from the bottle at the bottom back and put it back in the top while you're repeating the process to get the last of the air out. So long as the fluid is clean it won't do any harm (I'm assuming by bleeding it, you probably replaced all the old crap).

[vifferman]

The slave cylinder isn't leaking is it? The one on my FZR does that, and I get the impression its a common fault.

It's common to many bikes with hydraulic clutches. The VTR's clutch fluid went dark very quickly after I last bled it, and I suspect that was from leakage as apparently it is a problem with them too.