XS650 Clutch Worm Actuator experiment & tidbits

The finding neutral discussion is timely as I made an interesting discovery this past summer and just verified it again last weekend during my ride that I thought I would share.

Some of you may recall last summer (I think at the time I had posted up an issue I was having with a stiff clutch/lever issue and finally realized that I stupidly forgot to simply oil my clutch cable)...anyways, along with getting the clutch to move like butter (which it truly does now--it's so light and easy to pull) I also experimented with my shifter which I didn't really discuss since it wasn't part of the issue at the time...and here's the interesting part: I have been running with rearsets for quite some time now, and while I could shift just fine...I too had an issue with finding neutral, especially when hot...but this was not new to the rearsets as it was also kind of an issue when it was stock too. Since I had a few extra shifters in my box of parts I decided to try something and swap out the smallish shifter that mounts on the shift rod (and connects to the linkage of my rearsets) with a longer one. You can see the original one I had in this picture (it's black and is approx. 2" long)

I ended up using one that's closer to 3.5"- 4" (I'm not near my garage so don't have exact measurements but imagine the black shifter part in my pic being double it's length), and my finding was that not only could I shift WAY easier, but I've yet to NOT FIND NEUTRAL. It just dawned on me when I saw the last few posts on this thread pop up, and thinking back on my ride this past weekend-- that since I made the change, neutral has not been missed nor have I needed to rock the bike while sitting at a light or rev it slightly to find neutral. And that begs the question... why? I have to think that leverage and the ability to turn the shift rod with greater force is it work here...but I'm not sure the physics/nature of the forces to know how to calculate the variances of a rearset with a taller/longer "lever" vs. the stock shifter...perhaps it's nothing? But I thought I'd share and see if that adds to the mystery.
 
now that is really interesting !...
I'm thinking of fitting some forward controls on mine and am busy gathering odd bits from different models to coddle some Heath Robinson job together. the arm that I have is about 3" and it occurred to me that the longer lever arm might make shifting easier but I hadn't thought about the effect on finding neutral.
 
With less force being required to shift due to a longer lever, it makes sense that you would find neutral easier, given that you have less of a chance to yank past the slippery sucker. I wonder if transmission speed has anything to do with it, those of you that have issues with all stock equipment, if you run a lower idle speed, do you think that would make a difference? Perhaps the shifter paw is less aggressive if an angle than what it needs to be? If you changed the size of the fingers on the pawl and gave it more of a grabbing shape on the shift drum rods that contact the pawl, maybe it would have less chances of flying past neutral. Just kinda rolling with the punches here, I haven't the time to dig into this at the moment. Duty calls... As much as I don't like the 9-5 Set up I have at the moment, I'll be sure to keep an eye on this thread throughout my day today.
 
peanut said:
now that is really interesting !...
I'm thinking of fitting some forward controls on mine and am busy gathering odd bits from different models to coddle some Heath Robinson job together. the arm that I have is about 3" and it occurred to me that the longer lever arm might make shifting easier but I hadn't thought about the effect on finding neutral.
Click to expand...
Ya, I would be curious if anyone else with an extended lever arm (say 3-4") connected to either rearsets or forward controls has found a similar experience to mine with regard to finding nuetral?
 
After reading through this thread, I can see I’ve still got a long way to go with achieving a lighter clutch lever feel on my XS2. All this information is contained in my XS2 build thread, but I thought I would like to periodically add things that I am trying , to this thread.

So just to summarize where I’m at right now on my bike.
I have a 256 motor with a complete clutch assembly from a later model 447 motor, I also have the later model
( longer ) worm gear actuating arm.
I have new friction plates and new clutch springs.
The worm gear has been cleaned and greased.
New clutch cable from Mikes XS, Japanese made, that has been freshly lubed.
I have also tried severeral different cable routing methods to try and reduce friction.

The difference in clutch lever pull, between my 77 and my 72 is jarring. My 77 has a very nice light clutch, almost like a modern Japanese bike, my XS2 on the other hand? Well, I see forearms like Popeye in my future if I can’t make it better.
So today I channeled my inner 2M and decided that to start with I need some baseline numbers to gauge any future improvement by.
I hooked up my old school spring based fish scale to both clutch levers right at the end of the levers by the ball and measured how much force it took to pull the clutch in.

First my 77......at 8 lbs it’s starting to rotate the worm gear and by 10 lbs the lever has very smoothly pulled all the way to the handgrip. Like butter baby!

Now my XS2......It starts moving the worm gear at 18 lbs! And requires progressively more force to pull the lever all the way to the grip...in the range of 22-24 lbs. Something else I never noticed, when you pull the lever quickly, it seems stiff but smooth, but when I was pulling slowly trying to take measurements, you could actually feel the cable bind and I would have to pull harder to move it again.

Since I suspect my cable is a large part of this problem, the first and simplest thing to do would be , take the Motion Pro cable off of my 77 and try it on my XS2. And go from there.

I’ll let you know the results when I try that.
-Bob
 
Mailman said:
Since I suspect my cable is a large part of this problem, the first and simplest thing to do would be , take the Motion Pro cable off of my 77 and try it on my XS2. And go from there.
Click to expand...
Might also want to consider an XS400 clutch actuator. The arm is bent towards the worm instead of away from it. Less binding than the "what were they thinking" 650 actuator. Ebay has a few of 'em. Look for the 1L9 type. Every little bit helps...

1000-jpg.123834
 
Jim said:
Might also want to consider an XS400 clutch actuator. The arm is bent towards the worm instead of away from it. Less binding than the "what were they thinking" 650 actuator. Ebay has a few of 'em. Look for the 1L9 type. Every little bit helps...

1000-jpg.123834
Click to expand...

Ahh yes.....that looks like the custom made actuator that 2M designed. This sounds vaguely familiar, I think I might’ve read something about this. Hmmm.....I might have to peruse eBay! Thanks Jim!

Edit: OMG, now I know where I read it. In my own thread!! :laughing:
 
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The mailman and I have talked but Sorry? a mikes cable? What could go wrong? Two words that work for me; Motion Pro, my ONLY goto. We are waiting on a quote for say 10, MP clutch cables with a gray sheath. (MP is out of stock on the gray material 3-2019) I'll also suggest TDS added to the oil for cable lube. My planned initial cable lube drill is; TDS in mineral spirits til it flows out the other end, some drying time then oil.
Kinda funny; the Buell forum is full of whiners about HYDRAULIC clutch heavy pull. My used bike had a (common for this bike) slave leak. Per usual, the forum fix was $$$ aftermarket replacement parts. Ole gggGary said hmm; did a full strip, polish, and TDS dusting of sliding parts concentrating on the o-rings, of both slave and master, reassemble. No leaks (so far) AND light clutch pull. :shrug: ;)
 
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UPDATE:

I did lots of swapping stuff around today and taking measurements. And the results were surprising!
Here are all the variables I will be testing today.

The standard clutch cable , in silver sheath, that is sold by Mikes,
Motion Pro aftermarket cable,
The clutch actuator mechanism that I was using on my XS2 ( it’s from a newer year model) ,
The clutch actuator from my ‘77 XS650D

First up let’s examine some of the differences between the components.
The clutch actuating arms both measure 50MM long from the rotational center to the end of the arm.
The clutch actuating arm ( worm screw ) that I had bought to use on my XS2 was used from a newer model and measures 35MM from the center to the clevis pin.
6ACD42CE-2688-4FEE-9B19-3E450768FE88.jpeg


I was surprised to realize that the actuator arm on my ‘77 D was different. The overall length of the arm is identical but the clevis pin was located further from the center at 45MM.
73A402A5-F406-4DC0-A1C4-422E005B8C58.jpeg


Now let’s examine my two clutch cables. This is my brand new , drip oiled, silver sheathed cable from Mikes,
The cable diameter is 2MM , the Motion Pro is a 3MM cable.
59F04B07-85B2-4542-B095-5B1DB93567CA.jpeg


The other end of the cable is where some surprises lay. The bend of the Motion Pro is actually sharper than the one from Mikes.
36EADD7A-29E1-4BEA-9BBE-2D6AA85CB91A.jpeg


But it’s inside, where the big differences lie. The one from Mikes is just an empty metal tube. The Motion Pro is fully lined with a ( nylon? ) sleeve.

Motion Pro
910843A4-7B67-44AE-8214-96CC0FE1FDCE.jpeg


Mikes
2D72E41E-24DE-4C9A-A476-C4AD8698EA96.jpeg


For my experiments , here’s what I did. I routed the Motion Pro cable on my bike and fastened it into position as you would to install it. I also left my Mikes cable installed, so now I have both on the bIke.

I have the left side cover from my XS2 with my rebuilt clutch actuating mechanism mounted to it as normal.
I also have the side cover from my ‘77D with the worm gear mounted in it. I will simply be swapping covers back and forth and hooking them up to both cables and taking readings on how much effort is required to pull the lever with a fish weighing scale.

First my initial baseline reading , this was the bear that started me down this path.

Mikes cable and the worm gear that I was using on my XS2 with the clevis pin mounted at 35MM to center.
This set up is grabby and when you pull it slow you can feel a cycle of binding and breaking free.

Begin movement at 18lbs
Full lever pull 22-24 lbs
3 lbs to hold lever fully pulled ( cable binds and grabs )

Next up let’s try the Motion Pro Cable with the same worm gear ( note this cable came right off my other bike and has not been lubed )
Begin movement at 12lbs
Full lever pull 18lbs ( Motion is much more fluid, but still high effort )
5 lbs to hold position fully pulled

Next up , Mikes cable with the ‘77D worm gear
Begin movement 8lbs
Full lever pull 18lbs
4lbs to hold position fully pulled

Lastly, the best results came with Motion Pro cable and the worm gear from my ‘77D.
Begin movement at 8lbs
Full lever pull 12lbs
Hold lever fully pulled 4lbs

I think the single biggest improvement for reducing the amount of effort came from the clevis pin being located further out on the actuating arm there by increasing the leverage. The Motion Pro heavier cable and higher quality sheath greatly reduces friction, with substantially better numbers without even having been freshly lubed.

The trade off here, I suppose, is reduced actuating arm travel with the longer arm. I will admit to my ‘77 still being hard to find neutral when it’s good and hot. Perhaps the shorter arm gives a little more clutch plate spread and easier to find neutral? I don’t know for sure.

Here is my take away from this today. I have ruled out any problem with my clutch pack on my XS2 ( phew)
As soon as I moved the Motion Pro cable and side cover form my ‘77 and installed them on my XS2, it felt like the same sweet clutch I have come to love on my ‘77. And why shouldn’t it? I have the same springs and friction discs and everything in both bikes.

I don’t think I’m going to worry about trying TDS as a lubricant. If I can just drill a new mounting hole for my clevis pin , the same distance as my 77. And get another Motion Pro cable, hell I don’t even care that it’s not silver. Maybe I’ll disguise it somehow. I now know it’ll work like butter on my XS2.

Shame I just ordered a worm gear from an XS400 off of eBay. The arm on that XS400 is pretty short, I don’t know if I’ll be able to get the mechanical advantage of moving the clevis pin further out.
Anyways, I hope you guys found this useful.
Bob
 
Mailman said:
I don’t think I’m going to worry about trying TDS as a lubricant. If I can just drill a new mounting hole for my clevis pin , the same distance as my 77. And get another Motion Pro cable, hell I don’t even care that it’s not silver. Maybe I’ll disguise it somehow. I now know it’ll work like butter on my XS2.
Click to expand...
It would be interesting if you tested the TDS. You proved to me the motion pro cable is better. You might be able to improve it more.
I ordered a MP cable for my bike. The black doesn't bother me as I am not restoring to the level you are. Since cable color is important to you I believe gggGary posted MP address where they make custom make cables. You're going to have to get another one anyway, might as well be one you like.
 
Mailman said:
The trade off here, I suppose, is reduced actuating arm travel with the longer arm. I will admit to my ‘77 still being hard to find neutral when it’s good and hot. Perhaps the shorter arm gives a little more clutch plate spread and easier to find neutral? I don’t know for sure.
Click to expand...
The longer distance gives a greater mechanical advantage so the amount of force is less. Problem is travel of push rod is reduced.
I remember when I was riding my XS2 having to adjust my clutch cable at the lever between hot engine and cold engine.
 
Brassneck said:
Very nice write up. I'm a fan of the motion pro cable. with a bit of oil dripped down it, it's really really smooth.
Click to expand...

Thanks! Yeah I remember when I first went to that Motion Pro on my ‘77, I was really amazed at how smooth that clutch became.

GLJ said:
It would be interesting if you tested the TDS. You proved to me the motion pro cable is better. You might be able to improve it more.
I ordered a MP cable for my bike. The black doesn't bother me as I am not restoring to the level you are. Since cable color is important to you I believe gggGary posted MP address where they make custom make cables. You're going to have to get another one anyway, might as well be one you like.
Click to expand...

Actually I might still get some TDS, lighter still is always a good thing and the uses for that stuff is practically endless. Gary contacted Motion Pro about getting some custom made silver cables, they do make them but they were out of them for the time being. Still might go that route in the future. For now, I think I will order another Motion Pro, it’s just so much better.
 
GLJ said:
Be interesting to see if you have to adjust your clutch cable at the lever between hot and cold engine.
Click to expand...

My guess is yes, because that’s exactly what I do when I’m on my ‘77 if I’m on it long enough to get it really hot.
Finding neutral gets to be a pain until I mess with the adjustment at the handlebars a little.
 
Just to add to this... About how long does it take for these things to get "really hot" and how can I tell if I'm running it too hot. I got about 20 or 30 minutes on mine after a brief warm up, and never had trouble finding neutral..? Perhaps I'm no where near hot enough of a running temp for this to he affected? Is it expansion of metal causing a change in tolerances?
 

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