Honda CBR XX Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
20 Posts
Discussion Starter · #1 ·
Yo boys, my clutch will not engage what so ever. I've bled them twice and made sure 0 air was in the system. I also made sure the clutch master cylinder and the hydraulic piston was good. Checked all hoses and lines that is hydraulic or clutch related. Everything was perfect. My clutch will not build enough pressure for the bike to change gears. Someone please help. I've been at this for a day now.
 

·
Registered
Joined
·
843 Posts
Try reverse bleeding.
Use a syringe and push fluid from the slave bleed nipple up to the master cyl.

Also - make sure the reservoir is not over full - that can play havoc with the clutch.
 

·
Play, it makes life fun
Joined
·
2,161 Posts
Are you losing fluid? Sometimes those clutch slave cylinders will leak but the fluid doesn't drip out until a lot leaks out. Was the bike sitting for a long time?

Sent from my SM-N960U using Tapatalk
 

·
Registered
Joined
·
329 Posts
The clutch operating system on the Bird is a very simple system and easy to check.
So some checks (I'm an anal engineer so I like to start in one place and work my way through ruling out possibilities as I go so apologies in advance!)
1. Check the lever hasn't seized on its pin (unlikely)
2. Get lots of cloths and cover tank and panels ....... level the reservoir as best as you can by turning the bars and release the cover (possible air lock)
3. Refit the cover since you are bound to move the bars and possibly splash fluid.
4. Remove the 3x 8mm headed bolts that hold the slave cylinder to the front sprocket cover and pull the slave from the cover.
5. Pull clutch lever very gently and see if the piston moves ................ very careful here (although if the piston pops out it takes 5 minutes to bleed) ..... or just put a clamp loosly on the piston and body to save it popping out.
6. If the piston moves remove the remainder of the bolts holding the cover on. There will probably be a mass of oily gunge in there! Clean this out before pulling the clutch actuation rod out. Clean the rod well (check for straightness of the rod whilst you have it removed) and the area around the hole that the rod passes through. Replace rod.
7. If the piston doesn't move then either it is seized (possible) or the master cylinder isn't pushing fluid through (not common)
8. If all appears to be normal and the piston moves well then I would suspect that the clutch plates have stuck together (possible)
This is a checklist The Duck posted, the bike in question had been sitting of a while but still a good way to proceed.
I have in the passed seen the braiding on a rubber hose fail, allowing the hose to "swell" when the lever is pulled and not transferring the pressure to the slave cylinder.
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #5 ·
Try reverse bleeding.
Use a syringe and push fluid from the slave bleed nipple up to the master cyl.

Also - make sure the reservoir is not over full - that can play havoc with the clutch.
Believe it or not, I've actually tried that.
Are you losing fluid? Sometimes those clutch slave cylinders will leak but the fluid doesn't drip out until a lot leaks out. Was the bike sitting for a long time?

Sent from my SM-N960U using Tapatalk
This is a checklist The Duck posted, the bike in question had been sitting of a while but still a good way to proceed.
I have in the passed seen the braiding on a rubber hose fail, allowing the hose to "swell" when the lever is pulled and not transferring the pressure to the slave cylinder.
Is the push rod suppose to stay in the hydraulic piston? Whenever I had pulled the hydraulic cover off the push rod was actually stuck inside the piston. I had to separate the rod from the hydraulic piston.
 

·
Registered
Joined
·
329 Posts
The pushrod is separate from the piston. It can get stuck either from grease applied when it was assembled or from crud that accumulates through time.

A test for the master cylinder I would do is to disconnect the clutch hose, probably first at the slave end, blank the eyelet with your finger and thumb, and operate the lever. DO THIS SLOWLY, the pressure should build up a will squirt passed your fingers. Place dusters to catch the fluid, it will damage any paint it touches.
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #7 ·
The pushrod is separate from the piston. It can get stuck either from grease applied when it was assembled or from crud that accumulates through time.

A test for the master cylinder I would do is to disconnect the clutch hose, probably first at the slave end, blank the eyelet with your finger and thumb, and operate the lever. DO THIS SLOWLY, the pressure should build up a will squirt passed your fingers. Place dusters to catch the fluid, it will damage any paint it touches.
How come when I took the push rod out of the bike it was stuck in the slave cylinder but yet, my bike was working perfectly fine? But now that I've sperated the pushrod from the slave cylinder and cleaned everything up it doesnt want to work? My mastercylinder, and slave cyclinder are perfectly fine,
 

·
Registered
Joined
·
1 Posts
I know you said "your clutch won't build any pressure" but is the clutch slipping? Just wondering, as mine did that one day for no reason. Turned out it was the Very Little Hole in the bottom of the reservoir not returning fluid. Only takes a really small piece of crap to plug it.
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #9 ·
I know you said "your clutch won't build any pressure" but is the clutch slipping? Just wondering, as mine did that one day for no reason. Turned out it was the Very Little Hole in the bottom of the reservoir not returning fluid. Only takes a really small piece of crap to plug it.
That's interesting, I'll take a look.
 

·
Registered
Joined
·
407 Posts
G'day Bear,

All the above is good advice. I can add that the rod from the slave cyl to the clutch basket can be pulled out and cleaned.

When you put it back in it should hold the slave piston about a half inch off the sprocket cover while you tighten the three screws down into place. If it isn't doing this, then something is wrong with the slave or the master cylinder....or the clutch.

Check that when bleeding the clutch, you pumped the lever 3-4 times before holding against the handle bar and cracking the bleed nipple, and repeat....... I forget if the master cylinder is one that does not 'spit' brake fluid as you pump the lever (I place the white plastic lid inner on just in case)...... I stir and scrape any crud off the alloy into the old fluid before syringing it out and then bleeding the system with fresh clean fluid. I figure you have probably done all this...... but just in case......;)

Check the DOT rating of the brake fluid....... the BB uses DOT 3/4 mineral (from memory) not the higher racing spec (just in case it's the new fluid causing seals to fail). With age and lack of regular bleeding, old fluid can hold a lot of moisture and cause problems.

Maybe it's time for a m/c kit and a slave cyl kit?

(y)
 
  • Like
Reactions: Bear_xx97

·
Registered
Joined
·
20 Posts
Discussion Starter · #11 ·
G'day Bear,

All the above is good advice. I can add that the rod from the slave cyl to the clutch basket can be pulled out and cleaned.

When you put it back in it should hold the slave piston about a half inch off the sprocket cover while you tighten the three screws down into place. If it isn't doing this, then something is wrong with the slave or the master cylinder....or the clutch.

Check that when bleeding the clutch, you pumped the lever 3-4 times before holding against the handle bar and cracking the bleed nipple, and repeat....... I forget if the master cylinder is one that does not 'spit' brake fluid as you pump the lever (I place the white plastic lid inner on just in case)...... I stir and scrape any crud off the alloy into the old fluid before syringing it out and then bleeding the system with fresh clean fluid. I figure you have probably done all this...... but just in case......;)

Check the DOT rating of the brake fluid....... the BB uses DOT 3/4 mineral (from memory) not the higher racing spec (just in case it's the new fluid causing seals to fail). With age and lack of regular bleeding, old fluid can hold a lot of moisture and cause problems.

Maybe it's time for a m/c kit and a slave cyl kit?

(y)
Where's a good site that I could buy both rebuild kits.
 

·
Play, it makes life fun
Joined
·
2,161 Posts
I have always bled my brake and clutch fluid on everything I own with a mity vac pump.
Now I am changing everything over to speed bleeders from Speedbleeders.com they make things so easy.
Just a thought.

Sent from my SM-N960U using Tapatalk
 
  • Like
Reactions: Bear_xx97
1 - 12 of 12 Posts
Top