The only reason you would need to do that is if your lever had no lubrication and was hanging-up which would cause the clutch to slip, probably, from not allowing the master cyl piston to fully-retract from the cyl.
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The only reason you would need to do that is if your lever had no lubrication and was hanging-up which would cause the clutch to slip, probably, from not allowing the master cyl piston to fully-retract from the cyl.
timpilot
Well-Known Member
I don't know what's going on but three times in a row I've ridden 12 miles to work and everything was OK.
All three times, everything was OK leaving work in the afternoon.
All three times the clutch was slipping badly when I exited the freeway after 12 miles in 105-degree heat.
This all began after I rebuilt the slave cylinder.
When the clutch is slipping, the lever is "stiff" from the very beginning of the pull. When it is not slipping there is a little play at the beginning of the pull.
So, the symptoms are telling me that there is air in the system, and the air expands as it gets hot and creates unwanted pressure in the system, partially disengaging the clutch.
Throughout the process, the after-market adjustable lever, and its brass pivot were well lubricated with a high-temperature, high-pressure lithium aerospace grease.
I was able to reverse-bleed only after removing the lever and got a lot of tiny bubbles in the master cylinder after pushing about 40cc's of fluid into the system through the bleed port.
I haven't had a chance to test it in the heat, and may have to wait until next summer to know for sure, as we may be out of the 100-plus temps now. Forecast is for 90's for the next ten days.
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You may have air in the system, but you probably aren't getting the clutch to slip due to that. Brake fluid going one way but not the other may result in a stiff clutch, but air in the system will just compress and result in less pressure at the clutch pressure plate, and in more freeplay at the lever.
I think you should replace your master cylinder w/a new one, and also replace your rubber brake line if you haven't already. It sounds to me like you may have a spongy hose which isn't allowing the free movement of the brake fluid. The hose is collapsing and acts as a one-way valve, building pressure which doesn't allow the clutch pressure plate to grab/fully-engage. Maybe check your slave cylinder to see if corrosion is hanging up the piston in the bore. That is a simple cleaning.
I think you should replace your master cylinder w/a new one, and also replace your rubber brake line if you haven't already. It sounds to me like you may have a spongy hose which isn't allowing the free movement of the brake fluid. The hose is collapsing and acts as a one-way valve, building pressure which doesn't allow the clutch pressure plate to grab/fully-engage. Maybe check your slave cylinder to see if corrosion is hanging up the piston in the bore. That is a simple cleaning.
timpilot
Well-Known Member
Thanks for the suggestions, Fire-Medic. Makes sense to me. Currently, I'm doing other stuff to the bike. So it may be a few days before I get to test out the clutch.
huskyman510
Well-Known Member
I had all these issues your talking about, rebuilt clutch,rebuilt slave,rebuilt master. Still the same.
Finally worked out that if my lever was off to reverse bleeding was easy and got every bit of air out,
then the one tip that seemed to work and I havent had a problem since is not fill the m/c full, leave a bit of air in there for the fluid to move around. mine sits about half way on the sight glass.
Whether this is correct or not Im not sure but it works for me!
Finally worked out that if my lever was off to reverse bleeding was easy and got every bit of air out,
then the one tip that seemed to work and I havent had a problem since is not fill the m/c full, leave a bit of air in there for the fluid to move around. mine sits about half way on the sight glass.
Whether this is correct or not Im not sure but it works for me!
I had the same problem that he was talking about....when the clutch would get "hot" it would slip. I bled the clutch again....and ran a piece of wire thru the return hole in the M/C....never had that problem again.
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timpilot
Well-Known Member
Thanks, Husky! That gives me great hope I'm going to solve this. I'm still doing some electrical work, so I haven't had a chance to test my reverse-bleed yet. Hopefully I'll be able to get the bike nice and hot this weekend to test it out.
huskyman510
Well-Known Member
No Probs let me know how you get on, many frustrated nights I spent on my clutch. At least I know every nut,nipple and screw in regards to it now.
I didnt mention but I did the double clutch plate mod as well in a process of fixing my slipping plates.
As 'traumahawk' said, you have to have the two holes in the master cyl open and unplugged. The one closest to the banjo bolt for the hose is a small dia hole and you can use a pin to probe it open. Whe I reverse-bleed mine, I get air coming from both the holes. When most of the air is expelled, the small master cyl hole begins producing a steady stream of tiny 'fizzies,' small bubbles which seem to indicate most of the air is removed. When it stops having those 'fizzie' bubbles, you should be able to fan the clutch lever a few times and have a normal-feeling lever.
As I posted, I have had interally-collapsing brake or other hydraulic hoses which until I decided that was it, had me scratching my head. I've replaced them on cars, trucks, and bikes, usually older vehicles, as the hoses are normally quite-robust, and last a long time unless they are pinched or damaged.
As I posted, I have had interally-collapsing brake or other hydraulic hoses which until I decided that was it, had me scratching my head. I've replaced them on cars, trucks, and bikes, usually older vehicles, as the hoses are normally quite-robust, and last a long time unless they are pinched or damaged.
I'm wanting to say that the factory service manual says to replace your brake lines every 5 years....I wonder if its the same for the clutch?
wayne z
Well-Known Member
My '85 still has all the original hoses and they are fine.
timpilot
Well-Known Member
Early-on, I shone a flashlight through the fluid in the master cylinder and could see through both holes. I could pull the clutch lever and see the piston and O-ring sliding past the holes so I knew they were clear. When I removed the lever and back-bled it I quickly saw the multitude of tiny 'fizzie' bubbles coming from the smaller 'front' hole (the one closest to the banjo fitting).
After letting the bike sit a few days, the clutch feels good but feels a little stiffer after I pump the lever 5 or 6 times. So, I'm going to back-bleed it one more time before I go for a test-ride. I think I will back-bleed at the master cylinder banjo fitting before I remove the lever and back-bleed into the master.
I hope that documenting all of this will be helpful to someone in the future. And not just boring tedium.
The problem with the factory lines is that they are rubber, and tend to expand when you put pressure on them. If they expand with pressure, then not all of the pressure is going where it is supposed to....IE to the brake calipers, or to the slave cylinder, and this problem gets worse with age, because rubber softens and deteriorates.
When upgrading the brakes, why do you think one of the first things that people do, is to replace the lines with steel braided lines? They dont expand, so all of the pressure in the lines goes where it should.
That is probably the exception instead of the rule. Thirty year-old rubber deteriorates due to weather exposure, ozone in the atmosphere, and the usage it gets, I would be replacing something that old because my life depends upon its proper function, not because it hasn't failed, yet.
I gave-up rebuilding master cyl's as-long as I can buy the OEM or equivalent, because saving a few $ isn't as-important as proper function of the component and it's place in the system. Brake and clutch lines are cheap compared to an ER visit or worse.
And now for a stupid comparison:rofl_200:I buy a new toothbrush even though the old one still has bristles. 'Miles Long' told me to!
Glad the O.P. is getting to the end of his issues.
timpilot
Well-Known Member
Did another back-bleed from the upper banjo then into the master cylinder (m/c). Went for a 15-mile test ride and the clutch was slipping worse than ever at the end. I could only idle in 1st gear to get the bike to move at all. I ended up at the vintage bike show/sale at Eastside Performance Motorcycles in Mesa, AZ and got a lot of help from Dale diagnosing the problem. Seems the brass bushing in the clutch lever was tight and not rotating. Dale helped remedy that and I was grateful to be able to ride home. Clutch slipped just a tiny bit. Then the big discovery/revelation/duh moment. I realized the after-market adjustable lever was always difficult to install because the bolt hole wouldn't align and when I did get the bolt in, there was NO free play, meaning the lever was constantly applying a little pressure to the m/c rod and it got worse as everything warmed up. So, I ground off a little material from the pad on the lever to allow some freeplay. Haven't fully tested it yet but the clutch feels far more normal on a ride around the block. Many thanks to Dale and the fine folks at Eastside. I'll definitely be a customer in the future. Looking forward to the next show/sale.:clapping:
Glad that you possibly got it fixed, also very glad that you document this. It should help out someone in the future.
We all like Peter Egan's writings, right? He had something to say related to this. Years ago he took a cross-country trip in an elderly Ford and to tell you the truth I cannot recall if it was a Model T or an A.
Anyway, he said the trip went well, if slowly and while they had the occasional mechanical mishap, they were always able to get things fixed to carry-on. When they completed the journey, the vehicle's owner told him, ''you know, every part made by Ford functioned as it was supposed-to. The parts that failed were all aftermarket." Sometimes our desire to modify our bikes causes us problems we wouldn't encounter w/stock parts. If this was the problem, aftermarket levers, it wouldn't be the first post about it.
Anyway, he said the trip went well, if slowly and while they had the occasional mechanical mishap, they were always able to get things fixed to carry-on. When they completed the journey, the vehicle's owner told him, ''you know, every part made by Ford functioned as it was supposed-to. The parts that failed were all aftermarket." Sometimes our desire to modify our bikes causes us problems we wouldn't encounter w/stock parts. If this was the problem, aftermarket levers, it wouldn't be the first post about it.
huskyman510
Well-Known Member
+1, everything on my bike that ive had an issue with has been due to previous owner modifying things.
great little story
timpilot
Well-Known Member
I should have gotten a clue when I couldn't back-bleed the system without removing the clutch lever. I just didn't know enough about how the master cylinder works.
Do you know where the levers came from, so maybe that way people will stay away from them?
