Separate names with a comma.
Discussion in 'GS Boxers' started by atg, May 5, 2013.
Me too. Occasionally rough to 3rd but otherwise nominal.
Even if that were the case, it would still only pressurize the system like already discussed which would ultimately cause slipping and not rough shifting.
You can't envision that having the system so FULL that there is essentially no ability for fluid movement would cause issues?
These systems don't work by fluid movement; they work by pressure.
All the system does is this. The lever is pulled pushing a plunger into a bore which pressurizes the fluid down the hose pushing a ram on the other end which is a lever of some sort that disengages the clutch. The lever basically spreads the clutch pads apart, which only works with the friction created when they are pressed together by springs. When they are spread, there is no friction. It's a very simple system. The slipper part of the clutch is its own system that doesn't interact with the hydraulic actuation of the clutch.
The bladder in the reservoir allows a small amount of play in the system but it's main reason is just to force out a small amount when you close the lid so there is no air left. Basically, it's designed to cause a overflow when you put the lid on. The ONLY other place for "extra" fluid to go that ram mentioned earlier. In theory, if the system is overfull, the ram would be pushed out slightly as if the lever was pulled slightly. This leads to clutch not being fully engaged.
At the end of the day, there is no other place for fluid to go. The entire hydro system only works in one direction which is disengaging the clutch. Sure, there is a very small amount of vacuum created when the lever is released causing things to be back to normal but none that would prohibit the clutch from disengaging causing rough shifting.
All cogent, but I don't rule out some unexplained interaction between the master cylinder and the reservoir that we haven't thought of yet. We do have a few people who really believe their bikes shift better after this "fix". It could be the power of suggestion (i.e., doesn't ever car run better after it is washed?), but it could be something really odd we don't understand.
That's the thing I'm trying to figure out. I believe it really has worked for people, but it just doesn't make any sense WHY it worked. My guess is there is something unrelated to the hydro system but may be attached to the slave cylinder or something at the clutch.
Maybe even the theory about the slave being pressurized at rest is even semi-correct? In theory, if the system is pressurized already, the slave will be a very small amount extended vs a properly filled bike. This is what I was talking about where the clutch was semi disengaged. Now suppose when the lever is pulled to the grip, that slave cylinder is now extended to such an extent it's binding up the clutch to a small degree because it's spreading it too far. This sort of makes sense and would be a reason why shifting is improved. However, it's also a wild ass guess so take it for what it's worth.
I wish I could offer a detailed explanation but I cannot because I don't know. I hope it comes out over time so those of us with mechanical curiosity can be satisfied.
Regarding the power of suggestion: Nope. As an ex line moto mechanic who was often called upon to diagnose and fix problems that included clutch and transmissions, I have a pretty good ability to feel things when operating a bike. After lowering the fluid level, I can now get the kind of sweet, smooth shifting that a good transmission delivers. There is still a little notchiness sometimes, but none of the harshness that I would almost call grinding that it had before. Not imaginary.
Maybe there is a flaw in the design, and it is possible that BMW is going to produce improved parts, since a number of folks are saying they have been told this. I remain skeptical until such time as we see superseded part numbers.
Has there been any indicationas to what "parts" are going to be redesigned?
The clutch push rod is mentioned most, and other speak of BMW working on "new parts". I hasten to point out that I am simply repeating comments made on other forums, and they may or may not have any real basis in fact. That is why I remain a skeptic until I see new part numbers.
Just a two days ago I was all so very happy that the diffculty in finding neutral on my GSLC was history...
Today it started acting again and for no apparent reason. Just about every time I try to go from first into neutral it goes straight into second.
Nothing has changed, not even my shoes !
The same way I couldn't undertand why lowering the fluid level improved things now I can't understand how the great improvement obtained just went away ! Back to square one...
Hope it doesn't happen to others !
Only thought I can add is shifting is smoother when I give the clutch just a little blip as opposed to pulling it clear to the grip. Perhaps the decrease in disengagement is helping smooth the shifting.
Since I do not have enough miles on my bike to call it broken in yet. Only about 900. I do find that every time I take it out it gets better. The transmission gets better, the bike is starting to handle better as I get to know it better.
As far as the over filled clutch reservoirs a possible reason that removing some of the fluid is helping could be temperature changes. As the temperature increases the expanded fluid will have no place to go. Air compresses more then fluid.
That's also my suspicion. It must have something to do with temperature as my bike shifts normal when it's cold. The warmer the bike the more I have shifting clonks.
Anyway......I didn't take any fluid out of the reservoir. I just opened the top and let some fluid run out on it's self. Just a very little bit. The result was I could shift down to the 2nd gear the first time without noise when I rev up the engine a little bit between shifting. Upshifting didn't really change so I can talk about success for down shifting which actually causes the hardest clonks. But nevertheless. That can't be the solution in the end and also not the real cause of the clonks and clacks. I am 100% sure that BMW will come out with a solution soon!
Add me to the list of believers on excess clutch fluid. My bike didn't really have any shifting problems and shifts much better than the demo I rode, but I thought I'd give it a try and shifting feels even better. However, that's only one 15 mile ride after the fluid-ectomy and 300 miles total on the bike.
Finally, a real problem to report. For a while I though the bike was perfect.
My wife spotted this while helping me look for an E-clip that went flying while
installing some P3 lights. 600 mile service is scheduled for next Tuesday. They can fix it then.
Never did find the E-clip. Good think I keep some spares.
Happen to me also. Appear to come from inside by some kind of interference from the shaft. The material feels more thin and fragile comparing with the older models.
+1 on excess clutch fluid "fix". Have done about 60 commuting miles now and it definitely seems to shift smoother in the lower gears, although mine never missed any shifts beforehand. Bike has about 3000 miles on it. Instead of overflowing, though, the fluid was about 4 to 5 mm from top of reservoir after removing cap and gasket with bike on centerstand and reservoir as level as possible (bars turned to the right). I lowered it about 2 or 3 mm from there to see if it would make any difference, and it did as far as I can tell.
that pretty much sums up the entire bike. buy some cylinder head protectors, the metal thickness of the valve covers is 30% less than the oil cooled bikes.
They make improvements to try reduce weight and you guy's bitch and moan