| Author | Message | ||
     Tone |
2002 S3T - I opened up my clutch as part of the normal course of disassembly in order to get to my transmission. Upon reassembling the clutch, I noticed that it slips like crazy. This makes no sense, because nothing has changed, and it's not like you can put the clutch back together wrong. I have all the plates in the correct order. I took the clutch off 3 times and put it back on to make sure it's in place correctly and figure out exactly what presses on what and how the whole deal works, and I just can't see why it would be slipping. Does anyone have any ideas as to what is going on? Is it maybe normal that the clutch slips until it gets some transmission oil on the clutch plates? That is the only thing I can think of but that doesn't seem to make sense. Usually oil makes stuff slip more, not less, right? (I haven't put oil in the transmission yet. I don't want to get that far until I am sure the damn clutch is working.) The clutch slips so much that I can turn the belt drive sprocket by hand, and no, the transmission is not in neutral -- I can see the clutch spinning as I spin the belt drive sprocket, but of course the clutch hub is not spinning at all -- it puts some small amount of tension on the primary chain, but nothing substantial. Of course if the clutch was not slipping, I would not be able to spin the belt drive sprocket by hand due to the engine's resistance to being turned over. I did measure my clutch fiber plates stacked together and they came out 1mm over the minimum spec called out for by the service manual. The clutch was not slipping at all prior to disassembly. thanks for any ideas or suggestions you might have! | ||
| Sloppy |
Check spring plate and retaining ring -- sounds like there's no force on the clutch stack. What tool did you use to disassemble and reassemble the clutch? | ||
| Tone |
I used an aftermarket clutch spring compressor that is a copy of the Harley tool. It works the same as the Harley tool. I am pretty certain that the clutch spring is applying full pressure to the clutch pack. The only way it could not be applying full pressure is if: *The clutch spring is worn out - it's not any more worn than when I took the clutch apart, and the clutch worked fine before I took it apart. *The pressure plate is not as close to the clutch pack as it should be, such as if some piece of debris has gotten under it or there is some groove that it needs to seat in that it is instead sitting on top of. But from having removed/installed it three times now I am certain it is seated correctly in place and there is no debris *I forgot to put one or more of the clutch pack plates in place. This seems really friggin unlikely, since I did count them and didn't use them to play frisby while they were out of the bike... also I assume that if you somehow managed to loose one of them... failure to install even one plate would probably cause the clutch to not engage at all... my clutch is engaging somewhat... it does apply slight pressure on the primary chain. I did not compress the spring any more than was needed in order to be able to get the retaining ring out, and while I had the spring plate off the bike, I released the tension on the spring just to be extra nice to the spring. I have not reconnected the clutch cable or the compression ramps - all I have in place is the spring plate. This is all that should be needed in order for the clutch plates to lock together (for the clutch to be 'engaged.') The cable and ramp mechanism with the three ball bearings is only needed if you wish to 'disengage' the clutch. The only thing missing from the clutch pack that was there originally is oil... so... I am going to wet each plate completely in oil and them reassemble to see if that is the issue. My guess is the lack of oil is causing the slippage. If you have ever wrung gauge blocks together, then you know what I mean when I say perhaps one or more of the same mechanisms are at work in the clutch... here is a random page I found via google with info on those mechanisms: http://www.physforum.com/index.php?showtopic=3387 I'll post an update here in a few days after I have a chance to try to clutch pack with oil. thanks! | ||
| Tone |
oh yeah, to summarize the info from the link I provided above: "Wringability itself may be defined as the ability of two surfaces to adhere tightly to each other in the absence of external means. (They are not magnetized or clamped together.)" The surfaces need to be extremely flat and smooth in order to wring together. It is thought that the surface tension of the oil is one of the main mechanisms that causes wringing to happen. obviously a clutch pack is not as flat or smooth as gauge blocks, but it is still drenched in oil, so the surface tension of the oil may be the primary mechanism via which it functions. I am guessing that transmission oil has larger molecules than the oil used for sticking gauge blocks together, so maybe as a result the clutch plates don't need to be as smooth. | ||
| Sloppy |
Gauge block wringability works on a covalent bond (molecular) -- not surface tension. If you were to spray contact cleaner on them (hence remove any oil) they will continue to cling. If you keep them attached to each other for a long enough period they will no longer be accurate as they will transfer atoms from block to another - typically from the smaller to the larger. At least that's what the head diemaker told me... I used to work for a tool & die and etching plant. Sounds like you've done more than most in troubleshooting. Try the oil (you're supposed to soak them before installing), but if the clutch is spinning while disengaged it means that there's not enough force applied on the friction and steel plates. That force would come from the spring plate -- try working backwards from there? Why did you disassemble the clutch? | ||
| Tone |
Per some random web pages I found, oil surface tension is thought to be a factor in holding the blocks together in addition to covalent (sp?) bonding. How important of a factor, I don't know. I also found it stated that the thickness of the film of oil is subtracted from the true thickness of each block, so to get as accuracte a measurement as possible off of a stack of blocks, they must be wrung with oil. So I am thinking that maybe the lack of oil is allow my clutch plates to sit closer together and so the spring can't compress them as much. Heh. probably no? How to test that theory? I guess if I mic the distance from the spring backing plate to some feature on the clutch hub, and then I take some clutch plates out, then put the spring backing plate back in place, and mic it again, I can know if the backing plate is in fact touching the clutch plates or if it's bottomed out on the clutch hub. I wonder also if perhaps the friction plates are absorbent, and expand when soaked in oil? I'll have to mic them individually and also as a stack before and after soaking. That should allow me to test the sponge theory and also the oil film theory in so much as I am assuming the plates are flat. anyway, I also found some info that indicates that it is potentially a REALLY BAD IDEA TO ASSEMBLE YOUR CLUTCH PLATES WITHOUT FIRST SOAKING THEM IN OIL. Reason being that any slippage that happens before the oil fully washes up on them could damage the finish and thus reduce their holding capability. I disassembled the clutch because I needed to take off the hub to get to the detent plate which had busted free. I'll be posting some pictures and analysis from that adventure one of these days here, if I can ever get around to it... But basically, in a nut shell, if you're having trouble with shifter jamming up, I learned that kicking on the shift lever harder doesn't actually help - it actually breaks stuff. Who woulda figured. | ||
| Sparky |
3 things possible: 1) Did your clutch have a spring plate (not the spring with fingers) when you took it apart? If so, did you reinstall it or replace it with an extra steel and two fiber plates? 2) Maybe the retaining ring was not reinstalled properly? I refurbished the clutch in my S1 by removing the spring plate (the one that self-destructs after x amount of miles), smoothing the grooves caused by the rivets coming apart and installing Barnett plates plus the extra plates to compensate for removing the spring plate. But if I remember correctly, putting it back together was kinda tricky because the retaining ring would barely fit in its designated slot. Is it possible that you didn't squeeze the spring far enough to put the retaining ring in its proper slot to provide the correct pressure? 3) There is a smaller half-sized spring plate that is the first to go into the basket. If it were installed the wrong way, would it still provide spring tension? | ||
| Sparky |
I'm afraid I mixed apples with oranges. Regarding #3 in my previous post, the half-sized spring plate is a Barnett part and it consists of two parts - a damper spring and a flat steel seat ring. These two parts go into the clutch hub first followed by the series of fiber and steel plates. I guess the purpose of the Barnett damper spring plate and seat ring is to provide a certain amount of cushion to the clutching action when one runs all steel and fiber plates. Oh, these two parts are small enough to fit inside the first fiber plate. So whether they are installed or not, there is no net effect on the installed height of the disk pack. So, if you didn't install a Barnett clutch kit,.. nevermind.  | ||
| Tone |
I did add oil to the plates, and I found that the clutch slips much less with the plates coated in oil... But it still slips a lot. so anyway, long story short, oops. Turns out I had the main shaft nut on backwards. here are some pictures: Installing NUT, main shaft 37495-91 backwards results in interference with PRESSURE PLATE 37912-91, which results in massive clutch slip. And ya know, it would be one thing if I could attribute this to inattention, but no, I actually pondered for a few minutes which way to install this nut, and I chose the wrong direction. Good job! : - P It didn't quite look like it would fit in the recess the other way. It didn't bother me that it didn't engage all the threads because I know that once you have a few threads engaged, engaging more threads won't make the fastener any more reliable or stronger. It is rare, but sometimes you have a design with parts of variable dimensions, so you toss in a fastener that's longer than you need, so I guess I was maybe thinking this might be such a design. Obviously now that I think about it, it's not. But you know - first time taking a new toy apart, not sure how any of this stuff really goes together... anyway, my own inherent limitations aside, it would be nice if the parts book diagrams actually had renderings of the true parts, instead of using approximate icons... then you could tell which way a part goes without having to decipher the ambiguity in the drawing. On the same subject, it would also be nice if Harley/Buell updated the service manual one in a while too... It has lots of typos, for what you pay for it... well anyway. I'm happy. I'll finally have a running bike again. Or at least, a bike with one less issue : ) | ||
| Bad_karma |
Elliot Glad you found the problem. Tanks for the pictures. Now it's time to ride. Joe |
