-
Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password. If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?
-
Beginning April 1st, and running through April 30th, there is a new 2024 BMW MOA Election discussion area within The Club section of the forum. Within this forum area is also a sticky post that provides the ground rules for participating in the Election forum area. Also, the candidates statements are provided. Please read before joining the conversation, because the rules are very specific to maintain civility.
The Election forum is here: Election Forum
K75 clutch plate question
- Thread starter hstender
- Start date
gregfeeler
Dances With Sheep
Maybe I should have but I didn't see an ease way to do that and never had a problem with vibration or clutch operation. Others may have more informed opinions.
Reply yo Greg
Thanks, Greg, for taking the time to share your experience with me. I know the whole clutch assembly is balanced and should remain is enough configuration to each of its parts. So, I wondered if just replacing the friction plate would cause a vibration problem or an off balance problem.
Sounds like you had no issues. Thx.
Thanks, Greg, for taking the time to share your experience with me. I know the whole clutch assembly is balanced and should remain is enough configuration to each of its parts. So, I wondered if just replacing the friction plate would cause a vibration problem or an off balance problem.
Sounds like you had no issues. Thx.
Hstender,
Welcome to the forum!
The clutch disk repositions every time you pull in the clutch to shift. It is balanced by itself. The only alignment it needs is to be aligned with the centerline of the engine output shaft. This is done with a pilot tool. If not done, installing the transmission could be difficult to impossible.
HOWEVER, the three pieces of the clutch that are attached to the engine are not individually balanced to close enough tolerances. At the factory, they would put a paint mark on the heavy spot (or light spot. I never definitively found out which) on each piece. Then at assembly, the tech would align the three plates so that the marks were as far apart from each other as possible, thereby canceling out as much total imbalance as possible.
Since these marks are rarely visible after many years, it is critical to mark the three plates rotational relationship to each other BEFORE disassembly. Hopefully you did this, or you haven't disassembled it yet. Failure to properly align these plates will usually cause increased vibration.
The four rotating parts of the clutch including the friction plate in order of removal are: housing cover, clutch plate (friction disc), pressure plate, clutch housing.
When you're in there, at least replace the o-ring behind the nut that holds the clutch housing to the engine output shaft. This is the source of the majority of leaks in the clutch area. It drips directly on the friction surface. A rear main seal leaks behind the clutch housing. The o-ring is cheap and easy to replace. Rear main seal is about $45 and a bit more difficult, plus less likely to leak. Look for oil between the clutch housing and the back of the engine block if it is leaking at all.
Welcome to the forum!
The clutch disk repositions every time you pull in the clutch to shift. It is balanced by itself. The only alignment it needs is to be aligned with the centerline of the engine output shaft. This is done with a pilot tool. If not done, installing the transmission could be difficult to impossible.
HOWEVER, the three pieces of the clutch that are attached to the engine are not individually balanced to close enough tolerances. At the factory, they would put a paint mark on the heavy spot (or light spot. I never definitively found out which) on each piece. Then at assembly, the tech would align the three plates so that the marks were as far apart from each other as possible, thereby canceling out as much total imbalance as possible.
Since these marks are rarely visible after many years, it is critical to mark the three plates rotational relationship to each other BEFORE disassembly. Hopefully you did this, or you haven't disassembled it yet. Failure to properly align these plates will usually cause increased vibration.
The four rotating parts of the clutch including the friction plate in order of removal are: housing cover, clutch plate (friction disc), pressure plate, clutch housing.
When you're in there, at least replace the o-ring behind the nut that holds the clutch housing to the engine output shaft. This is the source of the majority of leaks in the clutch area. It drips directly on the friction surface. A rear main seal leaks behind the clutch housing. The o-ring is cheap and easy to replace. Rear main seal is about $45 and a bit more difficult, plus less likely to leak. Look for oil between the clutch housing and the back of the engine block if it is leaking at all.
Last edited:
gregfeeler
Dances With Sheep
Super!
Thanks, Guys. Great advice. I am aware of the balance marks and so on. I’m just having trouble getting information from guts who have only replaced the friction plate of the clutch. Generally, when searching anything about clutches on K bikes, all that pops up is lubing the splines. Or else the entire clutch is shot a d the entire assembly is replaced.
Thanks again. I suspected what Lee said, but wanted to be sure.
Thanks, Guys. Great advice. I am aware of the balance marks and so on. I’m just having trouble getting information from guts who have only replaced the friction plate of the clutch. Generally, when searching anything about clutches on K bikes, all that pops up is lubing the splines. Or else the entire clutch is shot a d the entire assembly is replaced.
Thanks again. I suspected what Lee said, but wanted to be sure.
I have replaced several friction discs while leaving the original other parts with no problems. You need to check how warped (dished in the center) the plates are. All used plates will have some dish due to heat. Too much will cause the contact area to be smaller which can lead to accelerated disc wear and possible slipping.
Too much?
Lee, your advice about about other parts being dished begs the question: how much is too much? Thank you very much for your help! The help provided on this forum is priceless and I greatly appreciate everyone who takes the time to read my posts and then actually type out their help to me and others.
Lee, your advice about about other parts being dished begs the question: how much is too much? Thank you very much for your help! The help provided on this forum is priceless and I greatly appreciate everyone who takes the time to read my posts and then actually type out their help to me and others.
I don't believe there is a stated spec. for that.
Lay a straight edge across each plate or put the two plates together so that they touch around the outside diameter and check the gap around the center. More than around 1/16" gap is starting to get up there and would be worth considering replacement.
It's not an exact science. It's more about do you want to make it last longer and work better or do you want to spend less now, but have to to do it again sooner and have to buy the extra parts then. The old Fram commercial; "You can pay me now or you can pay me later".
Your bike, your best judgement.
Lay a straight edge across each plate or put the two plates together so that they touch around the outside diameter and check the gap around the center. More than around 1/16" gap is starting to get up there and would be worth considering replacement.
It's not an exact science. It's more about do you want to make it last longer and work better or do you want to spend less now, but have to to do it again sooner and have to buy the extra parts then. The old Fram commercial; "You can pay me now or you can pay me later".
Your bike, your best judgement.
