Clutch issues 1983 cb650sc

[slodoug]

ok, PO said he rebuild the MC and replaced the line with an ebay one. I cannot seem to get much, if any pressure on the handle when trying to bleed it. I tried a brand new MC and it helped a little but still not enough to move he slave much. Piston barely moved. I've ordered a repl. bleed screw since theres almost no nipple for my hose to attach to making bleeding tough. Can I replace the line with a solid braided line? The current one uses metal portions attached to hoses and I dont trust it.

[Bob H]

Can I replace the line with a solid braided line? The current one uses metal portions attached to hoses and I dont trust it.

Sure, but it doesn't sound like the hose is the problem (or you would have a puddle of fluid on the ground).

If the master cylinder was replaced, I would take the slave cylinder apart and see what's going on. Pull the piston, wipe the surfaces with Sil-Glyde (or at least clean everything and lube with fresh fluid).

There's a lot of vehicles older than 1983 on the road with their original hydraulic hoses to brakes, etc. They can last a long time, even if they aren't perfect. Even if they swell a bit under pressure - which isn't going to be a lot of pressure on a clutch system compared to brakes.

I replaced my brake lines with braided, you could do that for your clutch but I think the real problem has to be the slave cylinder.

I've ordered a repl. bleed screw since theres almost no nipple for my hose to attach to making bleeding tough.

I would look for a complete slave assembly, and if no longer available get a good used one.

[Bob H]

PO said he rebuild the MC and replaced the line with an ebay one.

...I've ordered a repl. bleed screw since theres almost no nipple for my hose to attach to making bleeding tough.

The other thing is the Prior Owner likely was unable to properly bleed the system either. You could be pushing air.

[mollusc]

I replaced the clutch line on my 700S with braided stainless, but that was just to match the brake lines.  There was no real material effect.
My first guess would have been a blocked return hole on your master cylinder but since you changed that, the only thing left is really the slave cylinder.

[slodoug]

frustration:
master cylinder rebuilt, slave cylinder rebuilt. cannot get fluid to come out the bleeder screw at all. I had to take a clear solo cup fill with brake fluid and dip the MC end in it while i vacuumed from the bleed screw, then i was getting some fluid, but pressure wasnt building. Maybe im being impatient? So i took a brand new MC i bought, hooked up a brand new line and bled it, got pressure, but the clutch still didnt release. Thinking im going to need to take the plates out next.

[draser]

master cylinder rebuilt, slave cylinder rebuilt. cannot get fluid to come out the bleeder screw at all

You may want to check the correct installation of the "cup" seal on the master piston, which seems to not be pushing fluid when lever is pulled.

Just to confirm, when you pull vacuum from the slave bleeder... a) does the vac hold, and b) fluid level in reservoir stays the same ?

[slodoug]

vacuum holds, until i pump lever. thats on both the new and old MC. the kit already had that cup installed on it.
https://4into1.com/front-brake-master-cylinder-rebuild-kit-honda-cb-cx-gl-vf500-650-700-750-900-1000-1100-1981-1987/

[Gene]

I ordered a rebuild kit for the slave cylinder on my '85 CB 650 NH. Installed the kit, bled the system, and everything works as it should.

[draser]

vacuum holds, until i pump lever. thats on both the new and old MC. the kit already had that cup installed on it.

You may want to a) remove the banjo at the master, b) cover the hole with your finger, c) pump lever and see if pressure builds up (careful with splashing). There's an u-tube on that for verification of master operation after rebuilt.

I know kits come with seal installed, better to ensure orientation of seal is correct - these kits come from all over.

[slodoug]

update: had to replace the plates but got the clutch working with the setup shown. Now im trying to put the original master cyl back because the choke cable is part of it. that wonky clutch line is a pain to bleed. I even took a solo cup of brake fluid, dipped it in and vacuumed the other end. was getting some fluid but i think my tube on the bleed valve was leaking air. will try again in a week or so, right now i have the carbs out again to fix a float and change the throttle cables.

[slodoug]

im going to try the syringe method pushing it in and upwards from the slave to see if that bleeds better.

[Bob H]

...see if that bleeds better.

When I had trouble getting all air out, I put one of these "Banjo Bleeder Bolts" wherever there was a bolt for a hydraulic line. Especially helpful up top where a master cylinder connection would otherwise just use a banjo bolt. Bubble floats up there - BAM let it out with a bleeder. I think I got mine at Revzilla

https://spieglerusa.com/single-banjo-bleeder-bolt-20-02695.html

[Pete in PA]

Can I Ask a stupid question?  In that pic you have the clutch hose routed outside the bike. After you get all the air out you'll have to remove it to route it correctly negating all the bleeding, right?

[slodoug]

Can I Ask a stupid question?  In that pic you have the clutch hose routed outside the bike. After you get all the air out you'll have to remove it to route it correctly negating all the bleeding, right?

that was always meant to be a temp cable, its a tad bit short to route in place of the original. now that i know the plates are good, i'll reverse bleed.

...see if that bleeds better.

When I had trouble getting all air out, I put one of these "Banjo Bleeder Bolts" wherever there was a bolt for a hydraulic line. Especially helpful up top where a master cylinder connection would otherwise just use a banjo bolt. Bubble floats up there - BAM let it out with a bleeder. I think I got mine at Revzilla

https://spieglerusa.com/single-banjo-bleeder-bolt-20-02695.html

yeah i saw those on Galfers website, i like that idea..

[slodoug]

update, with the help of a big syringe and an upper bleeder banjo bolt, i reverse bled the original line and it all works now.