XS650 Clutch Worm Actuator experiment & tidbits

[TwoManyXS1Bs]

TwoMany---Great pix and write up. Any interest in selling a setup like that ??? tim

Thanx, timbeck! Welcome to my world, it's safe, they know me here.

I like to tinker and goof around with things. Not into any production/fab, not setup for it in this remote survival environment. But, there's several highly skilled fab guys here who may want to pick up on this. It's probably too early to lock in on this as I'm still experimentin', lookin' for the sweet spot with a combo cable/worm/pushrod configuration.

 

[TwoManyXS1Bs]

A 13/16" deep socket can be used for the inner worm protector, leaving having to find/make a suitable steel outer seal/cup protector. But, 13/16" deep sockets come in different lengths, and the outer pipe/tubing needs to be about 1.475" ID, and about 0.010"-0.020" longer than the socket, so its dimension can't be defined. This would be a cheaper solution. Maybe a threaded end with nut/coupler to adjust length?

 

[5twins]

Simple holder to make if you have a lathe ..... maybe you could put one (or two) out there as "loaner" tools?

 

[TwoManyXS1Bs]

Simple holder to make if you have a lathe ..... maybe you could put one (or two) out there as "loaner" tools?

Okay, 5Twins, fair enuff. I'm not happy with the 'black iron' part, need to get some regular steel for this. I'll make a couple more and post when they're ready. Probably need to write-up and include a 'how to destroy a perfectly good part' instruction sheet.

It's 33°F out here. Native-born Texicans don't like venturing out when it's below 60.


It's 75 feet to my barn. I'd never make it.




I'm wimping-out for the next few days....

 

[glennpm]

Love this thread!

I'm going to go with the fabricated/welded arm mod but am VERY interested in the correct moment arm length and your experience with the new cable from 650 central.

Appreciate your effort on this a lot!

 

[TwoManyXS1Bs]

Thanx, Glennpm. Yeah, still need to do the 1.5" arm length experiment. Have (3) new cables laid-out, measuring and examining (until that arctic norther blew-in). The EZ-pull cable is about 2" longer overall (53" vs 51" sheath) than the stock length cables, will see how that routes. I did notice that the strands are a finer/tighter braid than the other cables, and feels rougher. Will do some close-up pics of the various strands;

when it warms up a little...

 

[5twins]

I've heard the Easy-pull has a longer inner cable as well compared to the stocker? Can you verify that? I think 3M claims that gives a better angle between the cable and arm.

 

[TwoManyXS1Bs]

5Twins, yes, the EZ-pull has a longer inner cable, here's an early reference pic.

Top cable is a new, stock 447, middle is a new MikesXS (both have a .080" cable), and bottom is the EZ-pull .096" cable, about 1/2" longer.

 

[TwoManyXS1Bs]

Warmed-up a little today, so back into this. Double-checked the indicator, it's fine. But, neglected to do the finishing touches on the indicator holder, like tighten the nipple fitting, true/square the mount base, and re-clearance the inside. Re-ran the configurations and got new values, all a little off from the original. Of course, there should be some difference because these new tests were done with the reworked clutch pushrod ends, adjuster screw tip, and casecover entry hole. However, I feel more confident in these new values because of the alignment and stability of this new indicator holder versus my feeble attempts to get reliable/repeatable readings using a hand-held caliper depth guage.

Revised summary of the mods to date:

Configuration #1 - Stock XS1 worm, 1.3" clevis hole distance
Configuration #2 - Arm bent down 0.4", 1.3" clevis hole distance
Configuration #3 - Arm bent down 0.5", 1.7" clevis hole distance
Configuration #4 - Same as configuration #3, modified cable/elbow entry angle

#1: Pull-test = 25 lbs, Actuator travel = 0.062", Cable tension = 150 lbs
#2: Pull-test = 18 lbs, Actuator travel = 0.064", Cable tension = 108 lbs
#3: Pull-test = 14 lbs, Actuator travel = 0.046", Cable tension = 84 lbs
#4: Pull-test = 13 lbs, Actuator travel = 0.051", Cable tension = 78 lbs

 

[peanut]

thats quite impressive reductions in cable pull tension. Pity you couldn't get a reading for test #3 it would have been interesting to see the reduction obtained with straightening the bend only .

I imagine many cables follow the same torturous route that mine does at present. Another little job for the winter

 

[TwoManyXS1Bs]

thats quite impressive reductions in cable pull tension. Pity you couldn't get a reading for test #3 it would have been interesting to see the reduction obtained with straightening the bend only .

I made a thin wedge-washer (8° slope) (pics #1 & #2) that fit to the cable end to restore the cable entry angle to stock for configs #1 & #2. Figured config #3 would be of no interest to the audience, but you've got a point. Now I'm curious as well. It'll be easy to re-run for #3. So I'll do it and edit/update the above post.

I imagine many cables follow the same torturous route that mine does at present. Another little job for the winter

Oooh, ow, yeowch! Yeah, that's the factory original 30° elbow. Very draggy. After this next test with the new MikesXS worm, I'll be doing cable tests. One of the cables has your same elbow...

 

[TwoManyXS1Bs]

Received the new MikesXS clutch worm assembly ($52), quite anxious to try this out.

Pic #1 - This is a complete kit, replaces all worm-related parts. The steel worm threads are smooth and plated. The worm base body is a steel-shell reinforced black plastic that is harder than the original nylon part, but the thread surfaces look a little rough. Dry fitting and manipulating the assembled worm drive is quite revealing. This thing is super-slick! Almost feels frictionless compared to the original nylon, very high lubricity with this new plastic. Of course, grease will be used in the actual installation.

Will get base values of clutch lever pull force and worm travel with this new worm in its original shape. Then will perform the worm arm modification and take new measurements.

Pic #2 - Here's the first MAJOR problem. This new style of ball retention, a kind of thin square-holed washer swaged into the steel worm, is TOO SMALL to allow the clutch pushrod small-end to enter and rest against the ball. The clutch pushrod is an 8mm or 5/16" (0.315" - 0.312") steel rod. with a turned-down outboard section of 0.262" - 0.265" (6.7mm) diameter. The opening in the ball-retention washer is 0.240" (6mm).

Not good. Anybody attempting this installation will surely meet interference and fitting difficulties.

Pic #3 - Using a lathe to keep everything centered, opened-up the ball-retention washer opening to 0.285" (7.2mm). This will still retain the 8mm or 5/16" ball. The pushrod small-end now has plenty of room to enter without binding.

 

[peanut]

Received the new MikesXS clutch worm assembly ($52), quite anxious to try this out.

.

excellent!

Thats not good though regarding the tolerance for the clutch push rod ...Is Mikexs selling these as a bolt on replacement ? What do they actually do when they quality control check stuff in the Far East ? eye it up by eye probably .

I've seen some truly ludicrous stuff shipped out of the far East and imported to the UK for selling on online auctions. Some of it beggars belief like the fancy brass toilet roll holder .instead of keeping a master copy for quality control purposes they obviously picked out one from the production line to use every now and then.
Eventually the tolerance got so small that a toilet roll wouldn't fit in the damn thing but no one though to try a toilet roll before shipping 1000's of them round the World.

 

[5twins]

I have a question about your MikesXS clutch cable. Is that a recent purchase or one you bought several years ago? I ask because Mike's used to sell thick cables way back but changed to thin ones that are junk and break in as little as 400 miles. The word is out on them and I'll bet their clutch cable sales plunged. Maybe they've switched back to a thick cable now?

 

[TwoManyXS1Bs]

I have a question about your MikesXS clutch cable. Is that a recent purchase or one you bought several years ago? I ask because Mike's used to sell thick cables way back but changed to thin ones that are junk and break in as little as 400 miles. The word is out on them and I'll bet their clutch cable sales plunged. Maybe they've switched back to a thick cable now?

I bought this one a few years ago. It's 0.080" (2mm) diameter, smaller than the EZ-pull 0.100". Hopefully, if clutch cable tension could be reduced enough, the smaller ones would survive. In fact, I'm suspecting that smaller diameter cables might have a lower intrinsic friction. When this clutch worm experiment is done, I'm thinking about doing the clutch cable experiments as a new 'companion' thread with appropriate title.

 

[TwoManyXS1Bs]

Quick update:

Revised post #109 to show config #3 tests.
Revised post #111 to show pics of cablebase wedge.
Fixed missing zeros in travel reports, i.e. 0.61" is really 0.061". Can't believe I did that...

Made 2 more clamping jigs from galvanized plumbing pipe (pics #1, #2, #3).
Pic #4 shows how the worm is clamped in the vise, so that the arm can be rebent.

Also making 2 piloted countersink cutters with pilot guide, for doing the 8° recut of the clutch cable entry hole base.

Per 5Twins' recommendation, these will eventually go out to the XS650.com members as loaner tools.

 

[TwoManyXS1Bs]

Okay, now doing pull and travel tests on the new MikesXS clutch worm actuator. This is a different animal. When installed, it feels very loose and sloppy just as Mike Morris of 650Central remarked, but still very slick. The worm arm has 2 clevis holes, at 1.35" and 1.75".

Pic #1 - Fully seated, the outer worm arm clevis hole is a bit more retracted (at 4.8") compared to the stock XS worm (4.5").

With max leverage at the 3.7"-3.8" distance, and 0.6"-0.65" of cable travel, the ideal start point of the clevis hole would be around 4.3"-4.4". The stock clutch cable I'm using doesn't go that far, starting point is 4.1", so this worm will be almost 2mm up from the fully seated position.

Clutch lever pull and actuator plunge distances of new MikesXS clutch worm:

Configuration #5 - MikesXS worm, 1.35" clevis hole distance
Configuration #6 - MikesXS worm, 1.75" clevis hole distance

#5: Pull-test = 15 lbs, Actuator travel = 0.045", Cable tension = 90 lbs
#6: Pull-test = 12 lbs, Actuator travel = 0.034", Cable tension = 72 lbs

The clutch lever forces look about right, but the actuator travel values are way down. Doesn't make sense, I must be losing my mind.

Well, found out why. Read on.

 

[TwoManyXS1Bs]

Planning the rebend procedure, realized that the way this new worm arm is bent would require more finesse compared to the factory XS worm arm. Enter plan B.

Pic #1 - Close look at underside of the grease-seal shell, no spotwelds.

Pic #2 - Close look at top of the arm and shell, no spotwelds here, either.

Pic #3 - Decided to grind away the tack welds,

Pic #4 - And press the unit apart.

Pic #5 - It all comes apart. This worm arm can be reworked much more easily now.

 

[TwoManyXS1Bs]

Comparing the factory original XS worm (left in pic), to the MikesXS worm (right in pic), something looks different.

Do you see it?

????????????????????


The two worms are a different pitch!!!

The factory XS worm is a 4-start 8mm pitch, 32mm overall pitch thread.

The MikesXS worm is a 4-start 7mm pitch, 28mm overall pitch thread.
A finer thread pitch, yields less travel by a 7/8 ratio.

The two worm types cannot interchange parts. Pic #2 shows the worm bodies, they must match their respective worm drives.

Pretty sneaky way to reduce clutch lever effort.

Still plan to do the rebent arm test on this new worm, but need to rethink the ideal clevis hole position...

 

[DogBunny]

I came to this thread late, and only just started following it a week or two ago. I think this is perhaps the greatest thread ever?
I have run into the non-interchangeability issue just described, but I had no idea what the cause was -- I just knew that I had a drive that didn't fit into any of my bodies. Thanks for clearing that up, and for all of the rest of the work that you have put into this great thread.