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XS650 Clutch cable experiments and tidbits

Discussion in 'The Garage' started by TwoManyXS1Bs, Jan 20, 2014.

  1. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    XS650 Clutch cable experiments and tidbits

    This is a companion piece to the XS650 clutch actuator experiments:

    Clutch worm actuator experiment and tidbits
    Clutch worm mod testing
    Clutch pushrod experiment and tidbits

    I've rounded up 5 different clutch cables to be measured/tested/evaluated. They are:

    1 - 650Central EZ-Pull cable, 2.5mm (0.100") core diameter, no elbow.

    2 - Motion Pro 05-0013, 2.5mm (0.100") core diameter , 12° elbow

    3 - My old cable (16 yrs old, from Yamaha, similar to Motion Pro), 2.5mm (0.100") core diameter , 18° elbow

    4 - MikesXS 51-6502 (KSI 3L1-26335-00), acquired several years ago, 2mm (0.080") core diameter , 20° elbow

    5 - Yamaha 447-26335-00, 2mm (0.080") core diameter , 30° elbow

    The 650Central EZ-Pull cable is an elbowless, straight-in cable setup. The cable sheath end fitting that fits into the sidecover has a very small shoulder, so a brass shoulder was made and press-fitted onto the end. The free length of the core cable is about 1/2" longer than the other cables, a feature that is supposed to ensure that the clutch worm arm doesn't overtravel into the less-advantageous leverage zone. The core cable is also unique in that it isn't the single spiral wound type. It looks to be the 7x7 multi-strand type. The overall length of the cable is a bit longer than stock.

    The MikesXS clutch cable may be a different design by now, so it's tests may be outdated and irrelevant. If anyone has a new version, please post it up here.

    Please feel free to post up any additional, contributing, info on our clutch cables. Info on new/different cables, routing techniques, pro's/con's, whatever, are greatly encouraged.

    To reduce confusion, testing will be done in the above 1-5 order, and pics that show these cables will have the cables placed in the above 1-5 order.

    What we're looking for is any differentiating features that may lead to reduced clutch lever pull, increased worm/actuator arm travel, and clutch disengagement action. The cable core design will influence friction and tension stretching. The sheath must endure compression forces, and should have a liner to reduce friction. Three factors work against getting full mechanism travel; core stretch, sheath compression, and liner squash (the core tries to gouge into the softer liner on the short radius of a curved cable). I believe that increased tension of the core results in a non-linear compounded increase in friction, due to this gouging, and any reduction in cable tension will result in greater-than-expected reduction in friction. The notorious cable elbow must surely contribute to friction, hopefully these tests will quantify that effect.

    First, let's look at the cables:
     

    Attached Files:

  2. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Clutch cable barrel ends, that fit into the clutch lever.
    All cable sheath ends are 8mm diameter.

    1 - 650Central EZ-Pull cable, solid barrel end

    2 - Motion Pro 05-0013, solid barrel end

    3 - My old cable, worn/distorted plastic sleeve over smaller barrel end

    4 - MikesXS cable, plastic sleeve over smaller barrel end

    5 - Yamaha 447-26335-00, plastic sleeve over smaller barrel end
     

    Attached Files:

  3. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Pic #1 - To compare lengths, the cables were aligned at the sidecover sheath ends. The EZ-pull cable, with no corresponding elbow, was advanced 1.7", which is the effective length of the elbows.

    Pic #2 - The EZ-pull and Motion Pro cables were the longest, at about 53". The old/worn cable and Yamaha factory 447 cable came in at about 50 1/2". MikesXS cable is about 49 1/2".
     

    Attached Files:

  4. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Here's close-ups of the cable cores:

    Pic #1 - 650Central EZ-Pull cable, 2.5mm (0.100") core diameter, looks to be the 7x7 multi-strand type. Notice that the individual strands, at the outer surface, run in-line/parallel to the core axis. Does this affect friction?

    Pic #2 - Motion Pro 05-0013, 2.5mm (0.100") core diameter, single spiral wound type.

    Pic #3 - My old cable, 2.5mm (0.100") core diameter, single spiral wound type.

    Pic # 4 - MikesXS, 2mm (0.080") core diameter, single spiral wound type.

    Pic # 5 - Yamaha 447-26335-00, 2mm (0.080") core diameter, single spiral wound type.
     

    Attached Files:

  5. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Found this while examining my old cable. Can you see the three broken strands?

    Glad I have some new cables...
     

    Attached Files:

  6. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Here's some cable drawings and terminology from the Motion Pro website:
     

    Attached Files:

  7. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Various service manual extracts, Cable routing diagrams:

    Pics #1 & #2 - Left and right side of mid-70s standards, clutch cable routed on right side.

    Pic #3 - Left side of later-70s specials, clutch cable routed on right side.

    Pic #4 - Left side of last model specials, S/SG, clutch cable routed on left side

    While researching this, I found numerous manual pics of the left side (depicting other service routines unrelated to the clutch cable), where it can be seen that the clutch cable has been routed outside the left carburetor. In one unusual example, the service routine depicted the cable routed up in-between the carbs, and the following depection showed the cable outside the left carb.
     

    Attached Files:

  8. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Current clutch cable routing of my `71 XS1B

    Pic #1 - It's easier to route the clutch cable from the sidecover up through/behind the carbs, alongside the front of the rear downtube.

    Pic #2 - Emerge on the right side of the downtube/backbone area, keep alongside frame, inside the wiring harness. Then gently arc up alongside the backbone.

    Pic #3 - Stay above the fuel tank holding flange, arc around the neck/head, and keep all headlamp wiring between the cable and neck/head.

    Pic #4 - Emerge from around, and in front of, the wiring and neck/head, up between the speedometer and left fork tube capbolt.

    This routing will keep the cable out of the way of the odometer trip knob, minimize tight bends, yet give it the freedom to move while steering.
     

    Attached Files:

    highboy_coupe likes this.
  9. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Various service manual extracts, Clutch lever adjustment diagrams:
     

    Attached Files:

  10. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    The cable tests:

    Pic #1 - All cables will be pre-lubed with MMM's recommended PJ1 cable lube. Labling denotes that this PJ1 contains special extreme-pressure additives.

    Pic #2 - Here's the mechanism that will emulate the force of the clutch worm arm, spring load preset to about 70 lbs. The dial guage will reveal the amount of travel.

    Pic #3 - The first tests will be done on straight, unconstrained cables. This will establish base values for cable stretch. Cables with elbows are predicted to have reduced performance.
     

    Attached Files:

  11. Im curious to see your results. I just bought an ez pull cable for my 75 xs650b that I have not installed yet.

    I would also like to see the best way you found to adjust the cables. For the ez pull cable where did you buy that brass shoulder, was that to get it fit snug in the case?
     
  12. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Hi, estcstm3, thanx for your interest in this.
    Yeah, I should have expanded a little more on this EZ-pull cable fitting.

    Pic #1 - 650Central EZ-Pull cable, 2.5mm (0.100") core diameter. The cable end large diameter is 0.315" (8mm). The small projection diameter is 0.262" (6.65mm). The brass washer was made to snugly fit on the small projection, with an ID of 0.262" (6.65mm)

    Pic #2 - The sidecover cable entry hole diameter is 0.275" (7mm). This gives an annular support ring of 0.020" (0.5mm).

    While this cable does fit the application, I'm just more comfortable with a larger fitting base, especially since the cable experiences a minimum of 60-70 lbs of tension.
     

    Attached Files:

  13. Thanks for explaining that. I would have gotten it if I had tried but I couldn't visualize yet. Did you machine that brass ring yourself?
     
  14. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Yew betcha! Having a small lathe changes your whole perspective on maintenance challenges. If you're into wrenching, and ever thought about getting one, stop thinking and do it! It's a life changer!

    As far as reinforcing the cable end is concerned, you could go to some hardware stores with cable in-hand, and test fit some 1/4" washers. Many washers produced by overseas suppliers use 7mm as the hole diameter for 1/4", and you could easily fit one up. Make sure the OD of the washer doesn't exceed 9/16" (14mm)...
     
  15. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Been a while since posting on this experiment, been cold out there. Had some surprizes, unexpected results, had to do a slight redesign on the testing mechanism, came up with better calibration routines, replanned the testing, avoided freezing weather testing, and generally got lost in the black hole of clutch actuators and cables.

    Pic #1 - Testing one of the cables, straight/unrouted, to get baseline values.
     

    Attached Files:

  16. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    All cables were pre-lubed with PJ1 cable lube.

    Pic #1 - In the old days, before the cable pressure luber gadget, I would cut a v-notch in a spray-can nozzle hose, to fit in the small gap between cable core and sheath.

    Pic #2 - Then would hold the cable and hose together with my fingers, squeezing to get a good seal.

    Pic #3 - Sometimes would use a rag to improve the seal and keep from getting too messy.
     

    Attached Files:

  17. Brian902

    Brian902 XS650 Junkie

    This belongs in XS650 Tech section.

    It's a little late buy Yamaha should have had you in their R&D Department.

    Great info, well done!!!
     
  18. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Thanx, Brian902. For what it's worth, I did have a tiny influence in Honda's engineering.

    Cable tests - Straight/unrouted, RAW data

    The (5) cables were tested for full pull distances and dynamic pull force at the midway lever travel point. "Dynamic pull force" means the observed force while the clutch lever is in motion, being pulled-in.

    The tester was pre-loaded to three different values: 30 lbs, 40 lbs, and 60 lbs. The spring in the tester has a spring rate of 125 lbs per inch (about 1 pound per 0.008"), not exactly the same as the clutch worm lever (pushing the cumulative rate of the (6) clutch springs), but close enough to simulate their reactive force.

    All cables were adjusted to the minimum recommended lever play. Multiple readings were taken for each test, readjusting for slack/stretch, until stable/repeatable readings were acquired, then recorded.

    1 - 650Central EZ-Pull cable, 2.5mm (0.100") core diameter, no elbow.
    2 - Motion Pro 05-0013, 2.5mm (0.100") core diameter , 12° elbow
    3 - My old cable (16 yrs old, from Yamaha, similar to Motion Pro), 2.5mm (0.100") core diameter , 18° elbow
    4 - MikesXS 51-6502 (KSI 3L1-26335-00), acquired several years ago, 2mm (0.080") core diameter , 20° elbow
    5 - Yamaha 447-26335-00, 2mm (0.080") core diameter , 30° elbow

    -- <30 lbs preload> | <40 lbs preload> | <60 lbs preload>
    # - <Pull> - <Force> | <Pull> - <Force> | <Pull> - <Force>
    1 - 0.405" - 10.5 lbs | 0.375" - 12.5 lbs | 0.355" - 16.5 lbs
    2 - 0.475" - 12.5 lbs | 0.455" - 15.5 lbs | 0.435" - 19.0 lbs
    3 - 0.485" - 13.0 lbs | 0.465" - 15.5 lbs | 0.435" - 20.0 lbs
    4 - 0.425" - 12.0 lbs | 0.420" - 15.0 lbs | 0.405" - 20.0 lbs
    5 - 0.445" - 12.5 lbs | 0.425" - 16.5 lbs | 0.415" - 19.5 lbs

    Interesting results. The clutch lever pulls the cable barrel end about 0.60", and this distance is duplicated at the worm/actuator end when lightly loaded just enough to remove cable slack. This loss of pull distance calls for a rethink on the "Cable too short" warning.

    Concerning the mid-distance pull forces, they are pulling against the tester spring at half travel. If the travel is less/more than other tests, the 125 lbs/inch spring rate needs to be considered.
     
  19. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Next comes testing with the cables routed, up between and behind the carbs, and alongside the right side of the backbone, as per the older XS1/XS1B routing scheme. The tester was mounted at a location and angle to replicate where the actual sidecover's cable entry hole is located.
     

    Attached Files:

  20. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Cable tests - Routed on bike, raw data

    The (5) cables were tested for full pull distances and pull force at the midway lever travel point. The tester was pre-loaded to two different values: 30 lbs and 40 lbs. 60 lb preload was skipped because it probably far exceeds the typical xs650 cable load, and I burned-out on all this routing and testing. All cables were adjusted to the minimum recommended lever play. Multiple readings were taken for each test, readjusting for slack/stretch, until stable/repeatable readings were acquired, then recorded.

    1 - 650Central EZ-Pull cable, 2.5mm (0.100") core diameter, no elbow.
    2 - Motion Pro 05-0013, 2.5mm (0.100") core diameter , 12° elbow
    3 - My old cable (16 yrs old, from Yamaha, similar to Motion Pro), 2.5mm (0.100") core diameter , 18° elbow
    4 - MikesXS 51-6502 (KSI 3L1-26335-00), acquired several years ago, 2mm (0.080") core diameter , 20° elbow
    5 - Yamaha 447-26335-00, 2mm (0.080") core diameter , 30° elbow

    -- <30 lbs preload> | <40 lbs preload>
    # - <Pull> - <Force> | <Pull> - <Force>
    1 - 0.355" - 13.0 lbs | 0.330" - 16.0 lbs
    2 - 0.450" - 15.5 lbs | 0.415" - 18.0 lbs
    3 - 0.425" - 14.0 lbs | 0.405" - 17.0 lbs
    4 - 0.415" - 14.0 lbs | 0.375" - 16.0 lbs
    5 - 0.420" - 14.0 lbs | 0.385" - 15.0 lbs

    Also noticed that the midpoint relaxing pull values (slowly letting the clutch lever back out) were roughly half of the dynamic pull values, about 8-6 lbs.

    After all this cable flogging, decided to see if the cable free lengths increased/stretched any. Before/after measurements are:

    # - before | after | stretch
    #1 - 5.80" | 5.85" | 0.05"
    #2 - 5.25" | 5.35" | 0.10"
    #3 - 5.30" | 5.35" | 0.05"
    #4 - 5.25" | 5.30" | 0.05"
    #5 - 5.25" | 5.40" | 0.15"
     

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