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Do i need a clutch master cylinder overhaul kit?

Started by Storleer, November 21, 2016, 07:51:02 PM

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Storleer

These 2 pictures are taken from where the clutch lever pushes into the piston that goes into the master cylinder. I can see that the rubber boot there is torn. The lever also looks a little worn there. What do i do with this? Get a rep kit i guess, but should i also replace the clutch lever as well?

I have noticed that sometimes the clutch is difficult to fully disengage as in the lever not going all the way to the handlebar. I also removed the clutch slave and sprocket cover, but it is difficult to tell if there are any leakages from the slave unit because the cover, slave unit and everything around the sprocket was caked in an insane amount of dirt. Maybe i'll just get a rep kit for the slave as well. Is this a difficult job?

Flynt

Quote from: Storleer on November 21, 2016, 07:51:02 PM
These 2 pictures are taken from where the clutch lever pushes into the piston that goes into the master cylinder. I can see that the rubber boot there is torn. The lever also looks a little worn there. What do i do with this? Get a rep kit i guess, but should i also replace the clutch lever as well?

I have noticed that sometimes the clutch is difficult to fully disengage as in the lever not going all the way to the handlebar. I also removed the clutch slave and sprocket cover, but it is difficult to tell if there are any leakages from the slave unit because the cover, slave unit and everything around the sprocket was caked in an insane amount of dirt. Maybe i'll just get a rep kit for the slave as well. Is this a difficult job?

Replace the lever...  mine looked much better than that and wouldn't disengage a decent condition clutch.  Randy sells them... 

The slave is easy...  buy a new one from RPM and bolt it on.  You'll thank me later.

Frank
There's plenty of time for sleep in the grave...

Tor-King

I would highly recommend to rebuild the master.  If it is difficult to activate, a new rebuild kit will do wonders (along with the lever). Often this is maintenance that is overlooked. RPM is a great source: https://www.rpmracingca.com/proddetail.asp?prod=M%2FC%3AClutchrbkit

And...as Flynt suggested, the slave could/should be replaced.  That said, there is a rebuild kit for that as well.

Dean

1993 Yamaha FJ1200
1988 Yamaha FJ1200
1986 Yamaha FJ1200
1984 Honda Nighthawk S 750
1972 Yamaha XS-2
1972 Honda CT70
1974 Honda CT70
1992 Yamaha DT50 MX
2012 Honda CBR250R
2008 Honda CBR125R

Storleer

Thanks for answering :)

So i'll get a new lever and a new slave unit. I forgot to mention, i have a 84 fj1100. It seems that RPM do not have the master rep. Kit for my bike?


Storleer

Ouch, that MC rebuild kit was more expensive than i expected.

Maybe a silly question, but will there be a big difference between getting a repair kit for the SC rather than replacing the entire unit?

Storleer

After having a closer look i think i have found the culprit. The spring in the picture doesn't look right?

racerrad8

Quote from: Storleer on November 21, 2016, 09:37:12 PM
Ouch, that MC rebuild kit was more expensive than i expected.

Maybe a silly question, but will there be a big difference between getting a repair kit for the SC rather than replacing the entire unit?

There are a couple of different slave cylinder rebuild kits and yes they are cheaper that a new replacement.

O.E. Yamaha Slave Seal Kit
Slave Cylinder Rebuild Kit

But the condition of the slave bore is what is usually the deciding factor on rebuilding or replacing.

I do not stock the 1100 clutch lever but I can order it in without any issue.

Unless you are looking to keep the bike all stock, your best bet is looking for a used FJR1300 master cylinder on eBay.

Randy - RPM
Randy - RPM

Storleer

Quote from: racerrad8 on November 25, 2016, 10:57:25 AM
Quote from: Storleer on November 21, 2016, 09:37:12 PM
Ouch, that MC rebuild kit was more expensive than i expected.

Maybe a silly question, but will there be a big difference between getting a repair kit for the SC rather than replacing the entire unit?

There are a couple of different slave cylinder rebuild kits and yes they are cheaper that a new replacement.

O.E. Yamaha Slave Seal Kit
Slave Cylinder Rebuild Kit

But the condition of the slave bore is what is usually the deciding factor on rebuilding or replacing.

I do not stock the 1100 clutch lever but I can order it in without any issue.

Unless you are looking to keep the bike all stock, your best bet is looking for a used FJR1300 master cylinder on eBay.

Randy - RPM

I ordered a new clutch slave unit at RPM, and a new clutch handle on Ebay - got a NOS one for $15. Unfortunately the M/C rebuild kit at RPM was out of stock.

When replacing the Slave unit, this is bolt off/bolt on + opening the bleed valve on the new one, right? I've never done this before. From what I understand I should get something like a turkey baster/bleed tool to put on the bleeder valve, and open up the M/C reservoir, and while sucking out the old fluid carefully pour new fluid into the M/C fluid reservoir before it is empty and start sucking air.

I don't know which fluid is in the system, so I will replace all of it while i'm at it. DOT 3/4/5 brake fluid?

FJmonkey

How you bleed it can vary. It helps to fill the slave before you bolt the hydraulic line back on. Use new crush washers, cheap insurance against leaks. Then the party begins. You can bleed it the old school way using the lever to push fluid from the master. Having a catch bottle to prevent air getting back in is very much needed. Putting some Teflon tape on the bleeder fitting threads also help get a better seal. You can invest in speed bleeders, seems like a good idea, never used them myself. Or use a syringe and push and or pull fluid while adding/removing fluid as required. Or get the Mighty-Vac that many here say good things about.
The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

Pat Conlon

Yep, just as Mark said.

Use DOT 3/4 fluid (Unless the system have been converted to DOT 5)
Start with a full slave.
Use 2 new crush washers on the banjo fitting.
Teflon tape the bleeder screw threads.

To remove the old fluid from the reservoir I just use some paper towels to (carefully) absorb the old fluid. Carefully as in No drips (see below)  
Take this time to clean the m/c reservoir. Remove the bottom splash plate and clean out the crud collected below the plate.
 

Three methods can be used
1) Vacuum pump (MityVac) the easiest.
2) Reverse bleed (bottom up) next easiest. You need a syringe to inject the fluid at the slave bleeder port.(might as well buy a MityVac)
3) Traditional top down bleed. Takes the longest. In some cases overnight for the air bubbles to travel up the line to the m/c. Patience is key.

Be careful with DOT 3/4 It will eat your paint and bleach your black fairing inner panel. Lot's of towels and a spray bottle of water to neutralize the hygroscopic brake fluid is a good idea.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

Flynt

Quote from: Pat Conlon on December 09, 2016, 02:36:39 PM

Three methods can be used
1) Vacuum pump (MityVac) the easiest.
2) Reverse bleed (bottom up) next easiest. You need a syringe to inject the fluid at the slave bleeder port.(might as well buy a MityVac)
3) Traditional top down bleed. Takes the longest. In some cases overnight for the air bubbles to travel up the line to the m/c. Patience is key.


IMHO there is another path...

4) Before mounting Slave, do the top down method (3 with Slave full of fluid and fully compressed), but push the Slave piston in SLOWLY after you pump it out with the lever.  This technique puts all the air in the line and then uses the fluid in the Slave to push the air out.  In the final stages of this, you'll see a bubble free volume of fluid being pumped back and forth between Master and Slave.  I have seen Randy do it this way as well and it works as well as a MV.  I've also done it this way with great results.

Frank
There's plenty of time for sleep in the grave...

Pat Conlon

Well that's interesting Frank, thanks!

So, seeing as though you are the first to post this (that I know) you get to name the method. Something descriptive.

We will memorialize it over in the clutch files section.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

Firehawk068

Quote from: Flynt on December 09, 2016, 07:36:28 PM
IMHO there is another path...

4) Before mounting Slave, do the top down method (3 with Slave full of fluid and fully compressed), but push the Slave piston in SLOWLY after you pump it out with the lever.  This technique puts all the air in the line and then uses the fluid in the Slave to push the air out.  In the final stages of this, you'll see a bubble free volume of fluid being pumped back and forth between Master and Slave.  I have seen Randy do it this way as well and it works as well as a MV.  I've also done it this way with great results.

Frank

This is the recommended method for bleeding the hydraulic clutch on my Firehawk (LT-1 with the T-56)
It is how I did it on the car before bolting the slave to the bellhousing, and it worked well.  :good:
Alan H.
Denver, CO
'90 FJ1200

Flynt

Quote from: Pat Conlon on December 09, 2016, 09:03:07 PM
...you get to name the method. Something descriptive.

Not sure it has a name, but I learned it from a mechanic long ago.  Having seen Randy do it that way, I think we should name it the RPM method...  Maybe the Reverse Pressure Method?

Frank

PS - I left out a key bit...  some Master Cyls have a plate in the bottom of the reservoir, I think put there to keep a geyser of brake fluid from spraying out accidentally.  If you've got one of them, you need to pull it out so you can see the bubbles coming out when you compress the Slave.
There's plenty of time for sleep in the grave...