Next is to number mark the (6) pockets of the pressure plate, starting with the indexing hole.
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Yamaha XS650 Experimental Clutch
- Thread starter TwoManyXS1Bs
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- clutch experiment
Assemble the pressure plate, springs and screws. Run all screws down, but not necessary to fully torque them, just well seated.
Have the clutch pushrod adjustment screw about 1/2 turn (0.5mm) past its normal position. This should place the pressure plate about where it would begin to clamp the clutchpack. This way, all pressure plate spring loads are going thru the pushrod's mushroom, keeping the pressure plate floating, subject to the spring imbalances.
Put the trans in 5th gear, and use the rear wheel to rotate the mainshaft, and the clutch hub, so that you're not applying any forces to the pressure plate with your hands. Rotate slowly, and observe the runouts of the pressure plate.
Have the clutch pushrod adjustment screw about 1/2 turn (0.5mm) past its normal position. This should place the pressure plate about where it would begin to clamp the clutchpack. This way, all pressure plate spring loads are going thru the pushrod's mushroom, keeping the pressure plate floating, subject to the spring imbalances.
Put the trans in 5th gear, and use the rear wheel to rotate the mainshaft, and the clutch hub, so that you're not applying any forces to the pressure plate with your hands. Rotate slowly, and observe the runouts of the pressure plate.
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Temporarily mark the runout's "High" and "Low" spots.
If those High/low runouts align with the clutch springs, then swap the springs (and/or the associated screw) directly across the runout points.
If the High/Low spots are between spring positions,
Then swap spring pairs across those runout points.
In addition to parallel swapping, you can also try swapping those pairs in an "X" pattern.
Take another runout reading, note the High and Low spots, if they're different from the previous spots, and if the runout is less than before.
Erase the previous marks, keep the current marks.
Do the appropriate screw/spring swaps.
Repeat this madness until the runouts become acceptable. Also, cycle the clutch lever before taking readings. This would have the pressure plate settle normally with the new spring/screw distribution
When I started, the runout was 0.012" TIR. After only a few "swaps", the runout came down to 0.002" TIR.
If those High/low runouts align with the clutch springs, then swap the springs (and/or the associated screw) directly across the runout points.
If the High/Low spots are between spring positions,
Then swap spring pairs across those runout points.
In addition to parallel swapping, you can also try swapping those pairs in an "X" pattern.
Take another runout reading, note the High and Low spots, if they're different from the previous spots, and if the runout is less than before.
Erase the previous marks, keep the current marks.
Do the appropriate screw/spring swaps.
Repeat this madness until the runouts become acceptable. Also, cycle the clutch lever before taking readings. This would have the pressure plate settle normally with the new spring/screw distribution
When I started, the runout was 0.012" TIR. After only a few "swaps", the runout came down to 0.002" TIR.
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Lastly, carefully disassemble the springscrews and springs, one at a time, and label each with the number that corresponds to the pressure plate's pocket. This is now your magic matchup, to be used during clutch assembly...
Brilliant ME work here sir.
Bob Kelly III
Ranch Kid from way back,.... that got Old !
2M: I noticed you mentioned that the screws can be diferent lengths that hold in the clutch springs.....
wouldn't diferent length Screws cause a balance problem ? I mean if your going for the PERFECT clutch shouldn't all the screws be the same length to keep the balance as close as possable ???? just a thought !
.....
Bob.........
wouldn't diferent length Screws cause a balance problem ? I mean if your going for the PERFECT clutch shouldn't all the screws be the same length to keep the balance as close as possable ???? just a thought !
.....
Bob.........
2M another great thread. You have made me curious about the amount of run out my clutch has. One more job on the list for the off season.
Bob, the whole clutch is probably out of balance. The basket, clutch boss (hub), and pressure plate are all machined castings. Those subassemblies being geometrically symmetrical about the turning axis gets you close, but doesn't guarantee balanced. Kinda like wheels/tires.
The clutch speed is less than the engine, by the primary ratio of 27:72, which means that at an engine rpm of 2667 the clutch is spinning at 1000 rpm, which is enuff to cause vibration if there's a significant imbalance.
None of the clutch parts show any signs of balancing work, like the drilled holes in the alternator rotor. I haven't found any threads/posts on this kind of work. It may be worthwhile, but will require some sophisticated spinning fixtures, and be able to balance each subassembly independently. I'd be interested to know if anyone's pursued this.
Thanx, Signal.
Piling tasks onto the backs of others is what we live for...
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I've posted this before, but it was done as part of this true-up/tune-up process.
The steel plates have sharp edged tabs on one side, which may catch on the splines of the clutch boss (hub), and interfere with plate separation. An easy way to remove the sharp edges of the tabs is with a wire wheel.
Just barely introduce the tabs to the wheel, slowly turning the plate to get all the edges on one side of the tabs.
The steel in these plates seems rather soft, so go gently, just enuff to remove the sharpness.
Then move the plate to the other side of the wire wheel to get the remaining sharp edges.
Then, lap the steel plates, on a flat plate, with anything from #320 to #400 wet-or-dry. I wouldn't use coarser sandpaper, since I don't want a rough surface that would cut into the fibre frictions.
I wet the paper with brake cleaner. Then, placing my spread fingers atop the plate, like spider legs, use an orbital motion for several loops. Then rotate the plate 90°, and repeat this orbital sanding. After a full rotation, clean and inspect the plate. Unsanded surfaces are a giveaway to warped plates. Flip the plate over, and repeat. Doesn't have to be perfect. Just a simple deburring, deglazing, and inspection process.
Some debates on the plate orientation, manual excerpts recommend placing them with the (previously sharp) edges inboard, the rounded edges outboard, which would ease plate separation during clutch disengagement...
The steel plates have sharp edged tabs on one side, which may catch on the splines of the clutch boss (hub), and interfere with plate separation. An easy way to remove the sharp edges of the tabs is with a wire wheel.
Just barely introduce the tabs to the wheel, slowly turning the plate to get all the edges on one side of the tabs.
The steel in these plates seems rather soft, so go gently, just enuff to remove the sharpness.
Then move the plate to the other side of the wire wheel to get the remaining sharp edges.
Then, lap the steel plates, on a flat plate, with anything from #320 to #400 wet-or-dry. I wouldn't use coarser sandpaper, since I don't want a rough surface that would cut into the fibre frictions.
I wet the paper with brake cleaner. Then, placing my spread fingers atop the plate, like spider legs, use an orbital motion for several loops. Then rotate the plate 90°, and repeat this orbital sanding. After a full rotation, clean and inspect the plate. Unsanded surfaces are a giveaway to warped plates. Flip the plate over, and repeat. Doesn't have to be perfect. Just a simple deburring, deglazing, and inspection process.
Some debates on the plate orientation, manual excerpts recommend placing them with the (previously sharp) edges inboard, the rounded edges outboard, which would ease plate separation during clutch disengagement...
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Bob Kelly III
Ranch Kid from way back,.... that got Old !
2M: I agree completely it really shouldn't matter if the clutch basket and all its components are out of balance just so long as it's not way out of balance ! and as you said giving as how it's made kind'a assurs that it's going to be fairly close !
this is a fantastic thred ! Thank you very much ! ..... and next time I have my clutch appart I will definately take the wire wheel to those steel disks's teeth ! great tip there buddy !
.....
Bob..........
this is a fantastic thred ! Thank you very much ! ..... and next time I have my clutch appart I will definately take the wire wheel to those steel disks's teeth ! great tip there buddy !
.....
Bob..........
Nice write up again 2m........
1 point, i envisaged those steel plates getting snagged and ripped out of the hand and taking pieces of fingers and slapping them against the wall.............Even i would hesitate using a wire wheel...........a newbie........without experience it would be a given i recon
1 point, i envisaged those steel plates getting snagged and ripped out of the hand and taking pieces of fingers and slapping them against the wall.............Even i would hesitate using a wire wheel...........a newbie........without experience it would be a given i recon
The balance issue raised by Bob is interesting and in principle, he's correct that a balanced assembly would reduce vibration. I have three thoughts on it:
1) rotating out of balance forces vary with the square of the rotational speed, so cutting the RPM of the clutch ass'y to only 37% of crank speed (due to the primary drive ratio - as 2M points out) reduces any OOB forces to only 14% of what they would be without the speed reduction (0.37 x 0.37 = 0.14); That's an 86% reduction!
2) balancing an assembly like a wet multiplate clutch in mass production would be a nightmare - so many parts to handle and keep properly matched. Besides, with so many parts in the assembly, the darned thing likely averages out to "good enough" anyway.
3) the vibration caused by the reciprocating parts (pistons, rods, wrist pins etc.) on a 360 degree twin like the XS650 is so severe that it would simply swamp just about any simple rotating imbalance anyway.
Those are the reasons why MamaYama didn't bother trying to balance the clutch assembly in the first place.
Soooo, 2Ms work to improve clutch function is excellent and even if his various machining operations changed the balance of the clutch - the overall effect would be undetectable IMO.
Anyhow, keep going 2M - there's a Masters of Mechanical Engineering thesis in this my friend. ....which brings me to my question:
If I rode my bike down to Fredericksburg Texas and brought along some BEvERages, would you do this to my clutch?
Pete
1) rotating out of balance forces vary with the square of the rotational speed, so cutting the RPM of the clutch ass'y to only 37% of crank speed (due to the primary drive ratio - as 2M points out) reduces any OOB forces to only 14% of what they would be without the speed reduction (0.37 x 0.37 = 0.14); That's an 86% reduction!
2) balancing an assembly like a wet multiplate clutch in mass production would be a nightmare - so many parts to handle and keep properly matched. Besides, with so many parts in the assembly, the darned thing likely averages out to "good enough" anyway.
3) the vibration caused by the reciprocating parts (pistons, rods, wrist pins etc.) on a 360 degree twin like the XS650 is so severe that it would simply swamp just about any simple rotating imbalance anyway.
Those are the reasons why MamaYama didn't bother trying to balance the clutch assembly in the first place.
Soooo, 2Ms work to improve clutch function is excellent and even if his various machining operations changed the balance of the clutch - the overall effect would be undetectable IMO.
Anyhow, keep going 2M - there's a Masters of Mechanical Engineering thesis in this my friend. ....which brings me to my question:
If I rode my bike down to Fredericksburg Texas and brought along some BEvERages, would you do this to my clutch?
Pete
weaselbeak
XS650 Junkie
Some of us have long and intimate relationships with wire wheels, and we ain't skeered.......
Using my long and intimate relationship with wire wheel use also using a buffing wheel polishing metal, there are many factors that should be taken into account. Safety, Does, the operator have the experience to know how to handle the pieces, and be able to know the difference between a worn wire wheel or a new one.
It is an art........and there is not a truer saying that when using any revolving power tool treat them like, holding a bird............Hold it to tight and it will struggle, too loose and it will get away. ............ that art is mastered then an operator can be considered proficient in its use.............If some one is not proficient in its use then the part will snag and be ripped out of the operators hand and the resulting damage can be to the operator or the part.
The wire buffing wheel 2M shows has had a lot of use, the sides are worn, there is no shoulder on the wheel............A novice will not understand what that means, and if they have a wheel there is more than good chance that wheel will have the shoulder.
So back to why i posted my point............A warning to a novice...........Based on experience and as a safe practice warning..
It is an art........and there is not a truer saying that when using any revolving power tool treat them like, holding a bird............Hold it to tight and it will struggle, too loose and it will get away. ............ that art is mastered then an operator can be considered proficient in its use.............If some one is not proficient in its use then the part will snag and be ripped out of the operators hand and the resulting damage can be to the operator or the part.
The wire buffing wheel 2M shows has had a lot of use, the sides are worn, there is no shoulder on the wheel............A novice will not understand what that means, and if they have a wheel there is more than good chance that wheel will have the shoulder.
So back to why i posted my point............A warning to a novice...........Based on experience and as a safe practice warning..
Bob Kelly III
Ranch Kid from way back,.... that got Old !
if you continue along those lines of thinking Skull you'll soon not be telling anyone how to fix their machines ! it's impossable to know anothers abilities from a few statements, so are you going to put in disclamers under every use of a tool or it's Implied use ?
are you expecting us to ishue warnings to everyone on the use of a wire wheel if we sujest it's use ? we have to assume allot of things on this site. one is the persons ability to do the job that they are asking about, dangerous ot not. if they loose a finger in the proccess of changing a tire are we to blame ? just about anything under the sun is or can be Dangerous..... it's a given ...
..... I give up !
it's not worth it !
Bob......
are you expecting us to ishue warnings to everyone on the use of a wire wheel if we sujest it's use ? we have to assume allot of things on this site. one is the persons ability to do the job that they are asking about, dangerous ot not. if they loose a finger in the proccess of changing a tire are we to blame ? just about anything under the sun is or can be Dangerous..... it's a given ...
..... I give up !
it's not worth it !
Bob......
Thanx, Skull. Looking again at those 'wire wheel' pics, I can envision that too.
Hadn't really thought about it, I was trying to show the positional relationship of the steel disc tabs to the wire wheel, not realizing that someone may be looking at my "staged" one-handed finger hold on the disc, thinking that's the way to hold it.
I used a two-handed controlled grip to get the corner edges of the disc tabs to just barely kiss the wire wheel. I can't photo that on my smartphone, not enuff hands.
I have no issues with safety or other comments posted by folks who can see things thru different glasses. Enhances and embellishes the thread.
For me, sometimes just trying to get a concept posted is a challenge. Adding all the safety disclaimers would wear me out...
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Including the aforementioned maple syrup???
Fair warning, Pete. I'm a recovering workaholic, who gets carried away...
So am I 2M, so am I....
My dear Skull: I know that it can get a bit lonely down in the down-under part of the world.....but.....
Bob Kelly III
Ranch Kid from way back,.... that got Old !
Re reading this thread tonight has made me think .... and I regret what I said to Skull because he is correct in his cautions to the novis
especially with a grinder or wire wheel.... because it is one of the most dangerous tools in the entire shop.... people don't realize that, but it's true.... guards are commonly taken off the wire wheel so you can get to the tight areas of the work piece which increases it's danger !
I am sure everyone on this forum has had a wire wheel or grinder rip at least one thing out of their hand and toss it around the room more than once..... it happens and it's quite common.... but it's dangerous as hell ! to show you how dangerous I'll tell you a quick story so maybe you will be a bit more careful when using the wire wheel or grinder....
I was sharpening a old cold chisel it was very badly damaged from years of use and never been re sharpened so I decided to sharpen it and clean it up and take the mushroom off the end where the hammer struck it for years.... I had taken the guards off the grinder for some reason and haven't put them back on accept for the inside gard ... some how as I was grinding along and dipping the chisel in water to cool it , and swapping to the wire wheel every once in a while and then back to the grinding wheel the thing grabbed the chisel and threw it with such force that it went threw a 3/4" plywood board behind me... to this day I do not know How it missed me but it did.... now think of the force that it must have had to penetrate that 3/4" plywood ! if it would have hit me it would have made a hole through me ........this is the sort of thing 650Skull was warning people about and you don't have to be a Novice to encounter these dangers.....
I had to go out of the shop around the back and hunt for the chisel it went threw the plywood sheet metal wall and another 15 to 20 feet after it hit the ground at a steep angle..... and the hole in the plywood was not a round hole it was an oval so it didn't hit it end on....
I gained a bunch of respect for that big grinder and wire wheel after that incident and I put the guards back on it .
the force that it grabbed the chisel with was ungodly there was no way you could possibly hold it.... so a ring with sharp edges could and Would remove fingers just as easily as tossing a chisel through a wall.....
..... there are ways to use a grinder or wire wheel that REDUCE the danger but there is no fool-proof way that I know of to use one in real life.
hence the rub... because it can't be used properly most of the time it is a very dangerous machine.... and it can hurt you or kill you dead as a door knocker....in a hart beat....
.....
Bob.......
especially with a grinder or wire wheel.... because it is one of the most dangerous tools in the entire shop.... people don't realize that, but it's true.... guards are commonly taken off the wire wheel so you can get to the tight areas of the work piece which increases it's danger !
I am sure everyone on this forum has had a wire wheel or grinder rip at least one thing out of their hand and toss it around the room more than once..... it happens and it's quite common.... but it's dangerous as hell ! to show you how dangerous I'll tell you a quick story so maybe you will be a bit more careful when using the wire wheel or grinder....
I was sharpening a old cold chisel it was very badly damaged from years of use and never been re sharpened so I decided to sharpen it and clean it up and take the mushroom off the end where the hammer struck it for years.... I had taken the guards off the grinder for some reason and haven't put them back on accept for the inside gard ... some how as I was grinding along and dipping the chisel in water to cool it , and swapping to the wire wheel every once in a while and then back to the grinding wheel the thing grabbed the chisel and threw it with such force that it went threw a 3/4" plywood board behind me... to this day I do not know How it missed me but it did.... now think of the force that it must have had to penetrate that 3/4" plywood ! if it would have hit me it would have made a hole through me ........this is the sort of thing 650Skull was warning people about and you don't have to be a Novice to encounter these dangers.....
I had to go out of the shop around the back and hunt for the chisel it went threw the plywood sheet metal wall and another 15 to 20 feet after it hit the ground at a steep angle..... and the hole in the plywood was not a round hole it was an oval so it didn't hit it end on....
I gained a bunch of respect for that big grinder and wire wheel after that incident and I put the guards back on it .
the force that it grabbed the chisel with was ungodly there was no way you could possibly hold it.... so a ring with sharp edges could and Would remove fingers just as easily as tossing a chisel through a wall.....
..... there are ways to use a grinder or wire wheel that REDUCE the danger but there is no fool-proof way that I know of to use one in real life.
hence the rub... because it can't be used properly most of the time it is a very dangerous machine.... and it can hurt you or kill you dead as a door knocker....in a hart beat....
.....
Bob.......
