Rebuilding Slave Cylinder Fixed My Clutch

rjhartmann · 04-07-2008, 05:27 AM

Just to ratify this for some posters who have asked about inconsistent/rough shifting and sometimes slipping clutches ("how do I adjust my clutch?"):

Bought my Fi1 with 13K miles on it. Test ride revealed a slipping clutch so I paid accordingly. Brought it in for a 12K service and also had the clutch replaced.

Took it back the next day after shifting/clutch feel was not all that better and left it overnight. Mechanic (big dealership) said he re-bled system and yes, all clutch components including springs were brand new. Seemed better but not perfect so I decided that was how these bikes worked. Rode it for 10K miles like that.

When cold, 1st gear slipped in nicely, but whacked in when hot. Some upshifts were rough and clutch still slipped unless I launched just right. The key giveaway was that the clutch didn't seem to engage (in terms of lever travel) the same way consistently.

Steps taken:
1) Found corrosion on the actuation shaft. Easy job which did help smooth out engagement a bit so I stopped there for awhile. But the cold/hot dilemma remained.

2) Examined lever reservoir and noticed it had lots of gunk in the bottom. "Re-bled" it my a** - the mechanic probably never touched it.

3) Inside the slave cylinder the bore looked fine but the plating was rubbed off one side of the piston: The seal does all the work but still not a good sign. Something in there must have been dragging. Bore looked fine, though.

4) Bought rebuild kit (spring, cup, seal and piston) from Brian Silver Spares and installed. This involves emptying the lines so filling them again without air can be pesky. It's covered elsewhere in the forum. Got some surprise gunk when I blew air through the banjo bolts, btw.

While I was there I did an early engine oil change, 10-40 semi-synth. Never hurts.

The bike is like new! MUCH better shifting than when I got it at 13K. Smooth up AND down - where I didn't even know it had issues. SO much happier in traffic, going into and coming out of corners, etc. No more banging, plenty of feel, predictable engagement. What a difference!

So - it shouldn't come to this on these bikes but I hear about it too often. At least it's a cheap, easy bit of a job to clean the clutch shaft, replace the bits in the clutch slave cylinder and bleed the system. It eliminates doubts before replacing the clutch - and complements the process if you do.

dizzy · 04-07-2008, 06:08 AM

Interesting...hydraulic fluids are too often neglected. It's bad enough with simple systems, but now with linked brakes there's more components and brake lines to "throw in the mix". Anyway, I always like to lube and/or replace that little brass bushing in the clutch lever as well. Amazing how such a simple thing can make your bike shift so much better. BTW, Hon offers relatively cheap master cylinder repair kits as well. Ever noticed how some older bikes have that irritating "gritty" feeling in the front brake lever? I've had excellent results eliminating it by rebuilding the master cylinder.

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04-07-2008, 05:27 AM	#1 (permalink)
rjhartmann Junior Member Join Date: Dec 2006 Last Online: 05-08-2008 05:41 AM Location: London My Ride: '01 VFR800 Fi1 / '83 VF750R / '06 Paul Smart Rep/ '01 MH900e / '82 900SS / '78 900SS Posts: 8 Thanks: 0 Thanked 0 Times in 0 Posts	Rebuilding Slave Cylinder Fixed My Clutch Just to ratify this for some posters who have asked about inconsistent/rough shifting and sometimes slipping clutches ("how do I adjust my clutch?"): Bought my Fi1 with 13K miles on it. Test ride revealed a slipping clutch so I paid accordingly. Brought it in for a 12K service and also had the clutch replaced. Took it back the next day after shifting/clutch feel was not all that better and left it overnight. Mechanic (big dealership) said he re-bled system and yes, all clutch components including springs were brand new. Seemed better but not perfect so I decided that was how these bikes worked. Rode it for 10K miles like that. When cold, 1st gear slipped in nicely, but whacked in when hot. Some upshifts were rough and clutch still slipped unless I launched just right. The key giveaway was that the clutch didn't seem to engage (in terms of lever travel) the same way consistently. Steps taken: 1) Found corrosion on the actuation shaft. Easy job which did help smooth out engagement a bit so I stopped there for awhile. But the cold/hot dilemma remained. 2) Examined lever reservoir and noticed it had lots of gunk in the bottom. "Re-bled" it my a** - the mechanic probably never touched it. 3) Inside the slave cylinder the bore looked fine but the plating was rubbed off one side of the piston: The seal does all the work but still not a good sign. Something in there must have been dragging. Bore looked fine, though. 4) Bought rebuild kit (spring, cup, seal and piston) from Brian Silver Spares and installed. This involves emptying the lines so filling them again without air can be pesky. It's covered elsewhere in the forum. Got some surprise gunk when I blew air through the banjo bolts, btw. While I was there I did an early engine oil change, 10-40 semi-synth. Never hurts. The bike is like new! MUCH better shifting than when I got it at 13K. Smooth up AND down - where I didn't even know it had issues. SO much happier in traffic, going into and coming out of corners, etc. No more banging, plenty of feel, predictable engagement. What a difference! So - it shouldn't come to this on these bikes but I hear about it too often. At least it's a cheap, easy bit of a job to clean the clutch shaft, replace the bits in the clutch slave cylinder and bleed the system. It eliminates doubts before replacing the clutch - and complements the process if you do. __________________ www.LondonDOCGB.com 2001 VFR800Fi1 1983 VF750F 2006 PS1000LE 2001 MH900e 1982 900SS 1978 900SS

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04-07-2008, 06:08 AM	#2 (permalink)
dizzy Member Join Date: Apr 2008 Last Online: 08-11-2008 05:35 AM Location: MN My Ride: 07 VFR800 93 ST1100 Posts: 97 Thanks: 0 Thanked 1 Time in 1 Post	Interesting...hydraulic fluids are too often neglected. It's bad enough with simple systems, but now with linked brakes there's more components and brake lines to "throw in the mix". Anyway, I always like to lube and/or replace that little brass bushing in the clutch lever as well. Amazing how such a simple thing can make your bike shift so much better. BTW, Hon offers relatively cheap master cylinder repair kits as well. Ever noticed how some older bikes have that irritating "gritty" feeling in the front brake lever? I've had excellent results eliminating it by rebuilding the master cylinder.