Notch the slave cylinder gasket?

[twins4life]

I'm getting ready to install the new slave cylinder and want to get opinions on if I should notch the gasket to let the fluid drain out in case the slave leaks again. :banghead

[awagnon]

I just replaced mine on my '02 1150RT. I notched the gasket at about 6:00 position. Some file or grind a grove in the transmission. Others have drilled a hole in the both of the slave cylinder well. I'm not sure the notch will do any good, but I don't think it will hurt and may prevent hydraulic fluid from filling the cavity and tracking forward to the clutch.

[PGlaves]

With or without a notch or drain hole, your first line of defense is to be extremely attentive to the fluid level in the master cylinder. Fill it so with a known and repeatable orientation of the bike and handlebars the level is visible and memorizable. Any drop in the fluid level should be investigated immediately.

If your bike is a later-late model which uses mineral oil instead of DOT 4 brake fluid the oil could still foul the clutch and protecting the clutch with a notch or drain hole would cause little damage. However, if your bike uses DOT 4 brake fluid as hydraulic clutch fluid - then - remember that it can be corrosive when contaminated and at the very least will quickly attack and ruin paint and some plastics.

So weigh your ability and willingness to carefully monitor the fluid level, and the risks and rewards of trading off possible clutch damage to possible drainage damage.

[twins4life]

Taking into consideration that a hole or notch in the gasket may allow moisture to the slave cylinder area, I will go with Pglaves indea and just watch the fluid level of the DOT4.

Any drop in fluid level can mean only only one thing :banghead (in the absence of obvious leaks).

Thanks!

[awagnon]

Taking into consideration that a hole or notch in the gasket may allow moisture to the slave cylinder area, I will go with Pglaves indea and just watch the fluid level of the DOT4.

Any drop in fluid level can mean only only one thing :banghead (in the absence of obvious leaks).

I certainly can't argue with your logic and thinking. However, the space where the slave cylinder fits looks large, but it's almost completely filled by the slave cylinder. I wonder just how much hydraulic fluid it takes to fill it enough to start tracking forward along the throwout rod to the clutch. Mine had leaked quite a bit, yet there had been no obvious decrease in the clutch fluid level.

[PGlaves]

I certainly can't argue with your logic and thinking. However, the space where the slave cylinder fits looks large, but it's almost completely filled by the slave cylinder. I wonder just how much hydraulic fluid it takes to fill it enough to start tracking forward along the throwout rod to the clutch. Mine had leaked quite a bit, yet there had been no obvious decrease in the clutch fluid level.

I can only speak for the cavity on my R1150R and the one on Voni's R1100S - since those are the only two I've actually seen. There is a small space around the circumference of the slave cylinder inside the cavity, and considerable space forward of the slave cylinder. The hole forward along the clutch rod is centered in this space. On these two bikes at least, there would have been a visible drop on the fluid level in the reservoir before the fluid rose to a level to flow forward along the rod - IF - the starting level was within the sight glass window. If the reservoir is full enough that the top of the fluid is above the window you cannot monitor it very effectively. I like to set fill mine so that the top of the fluid is just visible at the top of the sight glass with a specific handlebar orientation best described as the reservoir as level as it can be. Then even a slight drop in fluid level is observable as the little crescent in the window grows.

[JimMoore]

Something else to think about. When mine failed, it sucked air in instead of expelling fluid. The fluid level actually rose.

[PETDOC]

After I had replaced the slave cylinder due to a failing bearing on my '04 GS I dutifully changed the clutch fluid, which I routinely replaced annually. When I removed the top to the handlebar reservoir to aspirate out the old fluid I noticed it was unusually very dark (blackish discoloration). Subsequently I read in a couple of posts that when the slave cylinder fails it will (can?) cause a dark discoloration to the fluid in the reservoir and you can use this as a sign of a failing bearing. Any thoughts on the valididty of this statement?

[twins4life]

After I had replaced the slave cylinder due to a failing bearing on my '04 GS I dutifully changed the clutch fluid, which I routinely replaced annually. When I removed the top to the handlebar reservoir to aspirate out the old fluid I noticed it was unusually very dark (blackish discoloration). Subsequently I read in a couple of posts that when the slave cylinder fails it will (can?) cause a dark discoloration to the fluid in the reservoir and you can use this as a sign of a failing bearing. Any thoughts on the valididty of this statement?

When I did my annual fluid change in May of 07 the fluid was DARK and pasty looking too. Wonder if that indeed is a sign of overheating (bearing failure)?

[PGlaves]

When I did my annual fluid change in May of 07 the fluid was DARK and pasty looking too. Wonder if that indeed is a sign of overheating (bearing failure)?

Darkening and discoloration of glycol hydraulic fluid (DOT 4 brake fluid) is usually caused by contamination. That contamination can be from moisture; it can be from a deteriorating seal; it can be from petroleum lubricants working past (and damaging) the seal.

I seriously doubt that a failing bearing would discolor DOT 4 fluid designed to take heating from brake components up to the 400 degree range (it varies by brand - I think the spec is about 360)

In any event - if you have darkened and discolored fluid a change is required at the least, and I would probably do further investigation to make sure the slave cylinder was not leaking.

[twins4life]

Darkening and discoloration of glycol hydraulic fluid (DOT 4 brake fluid) is usually caused by contamination. That contamination can be from moisture; it can be from a deteriorating seal; it can be from petroleum lubricants working past (and damaging) the seal.

I seriously doubt that a failing bearing would discolor DOT 4 fluid designed to take heating from brake components up to the 400 degree range (it varies by brand - I think the spec is about 360)

In any event - if you have darkened and discolored fluid a change is required at the least, and I would probably do further investigation to make sure the slave cylinder was not leaking.

Since the brake fluid was in about the same condition, I just figured the previous owner hadnt cahnged the fluids before as I just bought the bike and was peforming ALL services fresh.

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On another note, the RT has 30,000 miles. The service manual does not address the spline lube procedure, but since I am in this far... I dont want to create un-necessary work but dont want to close it up if the splines **NEED** to be lubed.

I did the spline lube job on my 1100R two years ago @ 35,000 miles. The splines were perfect, shiny and no wear / rust. I applied anti-seize and reassembled.

Back to my RT, opinions are to continue on and lube the splines, or just close it back up. BTW, the clutch push rod wont come out (even pulling it with pliars), it must be stuck on the pressure plate somehow.

And finally, the reason I am in here in the first place is the idle screech. And I wont know for sure the release bearing is the cause until I reassemble it. That would be a bad time to hear the noise is still present.

[JimMoore]

Subsequently I read in a couple of posts that when the slave cylinder fails it will (can?) cause a dark discoloration to the fluid in the reservoir and you can use this as a sign of a failing bearing. Any thoughts on the valididty of this statement?
That's what happened to me.

[PETDOC]

That's what happened to me.

Jim,
Curious did you notice the dark fluid first or did you first notice the slave cylinder failing?
Mine was first the slave cylinder bearing and then after replacing the slave cylinder I bled the clutch noting the very dark fluid. Because I change it yearly and never had seen it so dark I thought it odd, but did not make the still tenuous connection with the slave cylinder failure until reading the other posts regarding this possible relationship.
If the two are connected I presume if clutch fluid can leak past the failing bearing when the clutch lever is pulled in that the black grease I found between the slave cylinder and where it inserted into the back of the transmission could be drawn back up into the clutch fluid when the clutch lever is released.
Who knows, but if it is a sign of impending failure it would be nice to know.

[JimMoore]

Jim,
Curious did you notice the dark fluid first or did you first notice the slave cylinder failing?
Over a period of time I noticed my clutch engagement point getting closer to the handlebar, so I decided to bleed my cutch. The fluid was almost black. I didn't know it was the slave cylinder at the time, but I figured something was wrong.