The Alta Thread

Discussion in 'Electric Motorcycles' started by swamp, Jan 12, 2018.

  1. LocuL

    LocuL Gnarly Steward

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    Clutch is just a fossilburner oldschool thought of security. EV made it work in 1 tool. The throttle.
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  2. VxZeroKnots

    VxZeroKnots Long timer

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    I don't doubt the throttle offers great control. It's the human wrist I'm worried about. A finger is much more precise, especially over rough stuff.

    The Yamaha bike is a prototype works bike made to compete in E-trial, marketing and cost savings have no bearing on it. Yet it still has a clutch. Will the next gen have a mechanical clutch? Maybe not, they can probably synthesize the action with the motor controller digitally but you need a way to feed power out in a similar manner to make the chassis perform.

    The requirement has nothing to do with sitting on your ass paddling your feet "tractoring" up something. To do basic trials techniques like in the video above you need to modulate power in a manner the wrist just can't do well. Not to mention body position would be all out of whack if one tried.
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  3. Lutz

    Lutz Fuzzy Rabbit

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    E-bikes are already "throttle"-by-wire. "Clutch"-by-wire would be relatively trivial to add, in terms of power delivery. In other words, a secondary power-trim device in place of a traditional clutch lever; only instead of controlling a physical clutch, it controls another dimension of the power delivery map. I think this could work extremely well; imagine a very precise, consistent, one finger clutch.

    There are aspects of clutching a spinning engine mass that may never have a direct correlation into a direct-drive, electric drive line. That's probably OK for the vast majority of riders...even highly skilled ones in technical terrain.
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  4. LocuL

    LocuL Gnarly Steward

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    Valid point but electric engine delivers power on demand. I dont see the need. THe fossil 2/4stroke would need to deliver there peak power while doing the "thing". Thats why they need to clutch it. Have you tried an EV?
  5. VxZeroKnots

    VxZeroKnots Long timer

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    Only Ebikes at this time. Have you ever competed in trials or hard enduro at the expert amateur or above level?

    "Clutch" by wire! Now we're talking! Again, I don't think the issue is a limitation of the motor. It's both an ergonomic issue and speed/precision of movement issue. Think of playing piano with your fists rather than fingers. Yeah you can get a tune out but you can't make music. Now put the piano in the back of a truck on a bumpy two track.

    Power modulation with your fingers has been proven to work better by every trials rider ever. Could the same eventually be done or new techniques developed using just the throttle? Maybe, but something like @Lutz described is a good middle ground in the mean time.
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  6. dentvet

    dentvet Long timer

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    I was going to type that guitars sound better when played with two hands than with one hand, even the electric ones.

    I have a Zero dirtbike which is far less sophisticated than this ALta but I can see the same tendencies and limitations I recognize in my bike displayed in this video of an Alta. The "full torque at zero rpm" is a double edged sword that manufacturers have to design against for safety reasons so it only a theoretical advantage (see video intro..)

  7. LocuL

    LocuL Gnarly Steward

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    People rode 500cc 2 smokers on the edge. Lets admit. 500cc is a lot while keeping it within the rev range. On wrong twist and you are out.
  8. rainmaker8

    rainmaker8 Been here awhile

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    Pertaining to that (clutch feel versus throttle control) may be why Lyndon P changed his flywheel before Erzberg enduro? He swapped a heavier unit ... watch his R2P video . Maybe it helps lag the wind up just enough to get a bit more feel? Map 2 & 3 loft the front so easy, I am scared to try 4!
    About 6:00 minutes in he shows it:
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  9. LocuL

    LocuL Gnarly Steward

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  10. Florida Lime

    Florida Lime Long timer Supporter

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    I'm curious after seeing something in the Jo Momma thread about Prius problems with deep water -

    What would happen to an Alta that was dropped during a water crossing deep enough to submerge the motor ? :ear
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  11. Lutz

    Lutz Fuzzy Rabbit

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  12. Plawa

    Plawa ¿ʞO ǝʞᴉq ʎɯ sI

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    I have an EM Trials bike and a progressive clutch is my next purchase exactly for the reasons you mentioned - it has nothing to do with power, it's all about ergos - doing a double blip by twisting your wrist is a lot more awkward than just literally moving a finger.
  13. mminob

    mminob MotoHolic

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    Yeah what about the potential possible short circuit from the battery , grounding out and zapping the rider ? That might sting quite a bit ? It must have a ground fault protector type fuse or something , right ?

    The Supermoto version works great too ... Want one badly :-)

    [​IMG]
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  14. Trialsman

    Trialsman Been here awhile

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    I have been thinking about the power delivery and fine vs gross motor skills. The wrist is for larger movements with the fingers used for the finest of adjustment. Although, under most circumstances the Alta power delivery using only the wrist is sufficient, it could be even better. Seems like an electronic disengagement of the power would be the way to go on this style bike. With almost no penalty in weight or complexity, you should be able to wire in a lever in the normal place that would limit the current. This might not be an on/off but more of a potentiometer which would scale the current to the degree of lever movement. With little or no drag this could literally be a one finger fine adjustment for power. Even better this should be able to be made as a retrofit to any of the bikes (like mine) out there. Next step is to talk with some electrical engineers about the problem.
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  15. Plawa

    Plawa ¿ʞO ǝʞᴉq ʎɯ sI

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    That's exactly how it works on the EMs.. a PWM "potentiometer" actuated by a lever that sits in series with the throttle input. The newer bikes come with it stock, older bikes can be retrofitted since the ECU doesn't really know or care if the 0-100% input came from the throttle alone or from a combination of throttle/clutch.

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  16. Trialsman

    Trialsman Been here awhile

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    Thank you for the heads up on the EM clutch. I have reached out to him through eMail about buying a unit with the proper ends for the Alta. I will post the results when I find out.
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  17. Bt10

    Bt10 Long timer

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    I am just slightly confused... The guys looking for a clutch - are you looking for fine control, i.e. traction control, or are you looking for that clutch "pop" to get the front wheel up over a log?
  18. VxZeroKnots

    VxZeroKnots Long timer

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    I'm looking for the pop, and the wrist works fine for a single log. but a series of logs or ledges on some steep ass loose hill with the bike getting jarred everywhere using the clutch to control power is much easier. watch some graham jarvis videos and listen to the motor while watching his hands for example.

    Traction control and fine control are not the same thing, traction control just limits wheel spin which is sometimes necessary.


    I think expecting a "clutch" unit designed for an EM to work on an Alta is asking a bit much, though the principle is the same.
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  19. Ditch

    Ditch Long timer

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    for those not getting the clutch thing, in trials and other extreme competition you may transition from your ass on the rear wheel with arms straight out going down something steep to the handlebars in your chest going up some knarly ledge. It's difficult to control the throttle precisely so holding the throttle as close to one position and modulating the clutch to control traction happens. I suck at trials, but understand the concept (trials is loads of fun by the way).:1drink
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  20. ctromley

    ctromley Long timer

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    ***Confusion Alert***

    Let me see if I can talk you down here. EVs don't all of a sudden become a shock hazard when they get wet. The pack is isolated electrically. It has no potential relative to ground. "Ground" is a concept that makes sense when discussing mains power because mains power is referenced to ground. The only way you can get shocked when the pack is the only source of juice is to get deep into the high power bits and bridge across two things in there at different potentials. That's why you need training to work on that stuff. Dropping a wrench can get Very Exciting. So people use insulated wrenches and multiple interlocks and disconnects to limit the hazard. Always use redundant measures.

    If you're not inside the magic box, the risk of shock is minimal. When charging it can be a different story, because now the mains ARE involved. That's where ground faults come in. A ground fault is when there is an unintended connection, with some non-infinite resistance, between the normally isolated pack and the frame. If you now plug in the charger, which has its own isolation (that redundancy thing again), but its isolation fails, the frame becomes live and you can get shocked by touching it. Rarely lethal, usually ranges from a tingle to "YOW! THAT'S a problem!" Usually a voltmeter and a high ohm resistor is all you need to locate a ground fault so you can fix it.

    In the old hobbyist conversion days when we were using series-wound DC motors there was never a concern about getting them wet, even running submerged. Copper has MUCH lower resistance than water, so the vast majority of current still flows where it's supposed to and it runs fine. No mains involved, so no shock hazard. There was nothing 'electronic' in the sense of circuit boards in the motor or battery pack, so it was pretty water-resistant too. (Though an episode like that can let a lot of schmutz in, so it's an open invitation for a ground fault.) Getting your controller wet was asking for very expensive trouble, as you would expect from getting electronics wet.

    Nowadays the motors sometimes are electronically commutated (switching of the fields to get it to rotate), and sometimes that stuff is in the motor housing itself. In those cases the housing is waterproof. Controllers are waterproof too. Waterproofing is harder to do for battery packs, which now have electronic BMS and other functions, so generally that's where the risk is. In my electric car I know not to cross a stream that's more than a foot deep for that reason.

    On the Alta, the entire motor/controller/pack assembly appears to be in a waterproof housing, as it should be on a dirt bike.
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