Clutch Leak? Lost Some Fluid from the System

Kat600

Registered
About 6 weeks ago, I changed the fluid in my clutch line (Gen I, 2003) as the fluid was old and nasty. I also removed the front sprocket cover and cleaned all the crud out and cleaned the push rod and the rest of the piston (did not disassemble the piston). The push rod has a tiny bit of wear/corrosion on it, but still feels smooth for the most part.

About 4 weeks ago, I changed the friction plates and springs with OEM parts. The clutch worked great, but I noticed that the clutch was engaging with the clutch lever being much closer to the bar than I had been used to (about halfway or so). I knew this was simply the new springs and plates causing it to engage at a different point. No worries as I really liked where it was engaging now.

Over the last week, I noticed that the clutch was engaging with the lever further out and now it as engaging right at the end. About 2 days ago, I noticed that the fluid level in the master cylinder was down quite a bit.

I took it home, removed the cap and the diaphragm under the plate was sucked in pretty far. It looked like the fluid was down to about 1/2 way. I topped it up with fresh fluid and it shifts fine, but it is still engaging with the lever almost all the way out. I am worried that if something is wrong with the hydraulic system, that the clutch may start slipping and ruining my new plates.

Without removing the fairing, I couldn't see any leaks at the master cylinder, piston, or where the rubber clutch line meets the steel line (closest to the master cylinder). My plan is to remove the fairing to have a closer look as well as rebleed the system. I may even pull the piston out for a visual inspection.

Can anybody tell me what else I could look for that may cause the system to lose fluid? Should I have the piston serviced to see if there is anything wrong with it?Any other tips or tricks would be helpful as well. If it matters, the bike has 60,000 kms on it (approx 32,000 miles).
 
sounds like a similar prob to hong kongs post , my busa will loose almost a reservoir full in a 12month period , i think its due to muck from the chain getting around the piston seal .

just for the record my clutch lever bites about 3 quarters of the way out also
 
That is pretty common on some bikes is just wear interior on the clutch slevee after 20,000 to 30,000 miles I had mine done a few months ago, take the left fairing out pull the gear cover out , there is 2 screws to take the master cylinder losing the screws first before you pull the cover gear out that be easier, you can take the part to be rebuilt or buy it new it's a less then a 50-70dls job if you do it yourself pretty simple job or take it to a mechanic for about 130 bucks tops. Good luck.:thumbsup::thumbsup:

God bless!
 
Thanks ya'll! I was planning on inspecting the slave piston seal this weekend and doing another bleed before ordering parts. I'll let you know how it works out!
 
Quick Update: Removed front sprocket cover with slave attached and actuated the clutch lever on Saturday. As the piston moved outwards, I could see 1-2 tiny air bubbles coming up from around the side. $14 later and a new cup seal and spring are on the way. I have a feeling that once I replace those, I will be back in business.
 
Any news?.... I am very keen to hear if you've cured the prob as my clutch too picks up very late since bleeding the fluid and I can't find anything wrong with it, slave cyl etc!
My bike has less than 4k on it (07) so it's not wear, it's definitely something I've done when bleeding it. Cheers.
 
Tonight I put on a new galfer braided clutch line, cleaned and rebuilt the piston with a new cup seal and spring. Clutch engages almost at the same spot, maybe with the lever a hair closer to the grip, but at least I know that all the components have been replaced. I'll just have to live with where the clutch is engaging I guess. The cup seal was worn enough that it was leaking so at least I know what caused the fluid loss. Here is a picture of the old vs new seal. The new seal is on the left and the old seal is on the right. $60 for the new line and $14 for a new seal and spring, so not bad. I probably didn't need the line, but at least now I won't have to worry about replacing it ever again.

IMG_2216.jpg
 
Yeah, I don't think I've got a leak but I have the same lever problem. I put some 'chazzos' on it so that I have more adjustment on the lever which helped a bit. The only other thing I've found after hours of trawling this forum is someone suggested that this could be caused by wrong fluid and to use DOT 3 only. Not sure about this but I used DOT 3/4 so I am going to try. I'll let u know!!
 
Kat600.. I owe you one! I stripped it down for a fourth (or so) time and having read your last comments checked the seal on the slave piston VERY carefully.... There is the tiniest leak, not enough to see fluid drip out but just enough to stop the system pressurising fully when the lever is pulled. I'm hoping this is my problem. Have ordered a new seal kit and am looking into investing in a billet housing. Better quality than the original, looks nicer and also negates the need for the slave cyl support bracket. Thanks for your help.
 
Kat600.. I owe you one! I stripped it down for a fourth (or so) time and having read your last comments checked the seal on the slave piston VERY carefully.... There is the tiniest leak, not enough to see fluid drip out but just enough to stop the system pressurising fully when the lever is pulled. I'm hoping this is my problem. Have ordered a new seal kit and am looking into investing in a billet housing. Better quality than the original, looks nicer and also negates the need for the slave cyl support bracket. Thanks for your help.


your going to be disappointed im afraid the clutch is working properly and you have a solid lever so NO free play in the hydraulic system .

lever span only .

its just like a brake calliper self adjusts to keep fluid free play at a minimum

hth
 
Hmm, I understand what yr saying but I've checked the master too and can't see a problem. It is supposed to be a sealed system so if there is even the slightest leak where pressure can be lost that must be bad. I'll keep my fingers crossed and hope you're wrong!!!! Thanks
 
Back
Top