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Author Topic: How does clutching work? Springs, helix, weights, etc...  (Read 4198 times)

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DVS_DAN


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How does clutching work? Springs, helix, weights, etc...
« on: February 25, 2014, 04:04:54 PM »
  • I want to know more about the in's and out's of clutching.  I assume it is similar for any clutched vehicle, snowmobiles, 4-wheelers, RZR's...  The weights, cams, springs, and helix all affect the fully engaged clutch-in point, rpm's, acceleration, top speed, and maximizing the power of the vehicle.

    I'm curious if anyone has a good enough understanding to break it all down?   8)
    But I don't want greeting cards. I want to get fucked up on trampolines
    Pretty much everything that DVS_DAN said is correct.

    T-CAT


      "Yeah...I still float around here"

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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #1 on: February 25, 2014, 06:10:22 PM »
  • I can change springs, but as far as rebuilding them i usually just farm them out
    2000 yzf600r 2010-2013
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    636



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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #2 on: February 26, 2014, 02:18:45 AM »
  • I have a firm understanding of clutching after doing several custom clutch kits on my last few sleds.  There is a lot of basic info to master first:


    http://www.gates.com/brochure.cfm?brochure=1033&location_id=542

    http://www.totallyamaha.com/snowmobiles/aaTECH/tuning/tuning.htm

    http://www.thumpertalk.com/topic/764543-snowmobile-clutching-theory/


    et.,al.


    After that, discussions for specific applications are possible.  No two machines, riders, or environments are the same... so it really becomes a case-by-case examination.

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    DVS_DAN


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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #3 on: February 26, 2014, 08:58:24 AM »
  • I can change springs, but as far as rebuilding them i usually just farm them out
    Not interested, I just want to know the concept before my phone interview with Polaris ;D 

    636 nailed it with how many factors are involved.  More times than not, people say to just throw in the weights and try em.  A different rider's weight and everything come into play.  I just need to break it down into simpler parts, before understanding the plethora of cause and effects.  I'm gonna run through those links, thanks!


    MotoJ


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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #4 on: February 26, 2014, 12:49:50 PM »
  • Not interested, I just want to know the concept before my phone interview with Polaris ;D 

    636 nailed it with how many factors are involved.  More times than not, people say to just throw in the weights and try em.  A different rider's weight and everything come into play.  I just need to break it down into simpler parts, before understanding the plethora of cause and effects.  I'm gonna run through those links, thanks!



    As a Parts guy I can tell you one thing for sure...

    Ski-Doo Guys don't seem to re-clutch perfectly good sleds nearly as much as Yamaha/Polaris Fellas.

    There are Volumes written on any particular sled forum and there are more and more fine tuning options all the time it's crazy what you can tune on a stock setup without really doing any major work/parts these days.

    Best mod for the money from what I understand is the TEAM clutch Secondary with Hollow Jackshaft and TEAM Helix.

    Bone Stock, all things the same it is good for approximately 10 Sledlengths on identical sleds based on our basic testing.

    it shifts up and down like a dream and drops rotating mass..  Best, if not only Mod we are seeing on late Model hotrodder sleds.
    I was sliding down the track wondering "Is that my bike?" then it hit me.

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    DVS_DAN


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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #5 on: February 26, 2014, 01:32:59 PM »
  • Best mod for the money from what I understand is the TEAM clutch Secondary with Hollow Jackshaft and TEAM Helix.

    Bone Stock, all things the same it is good for approximately 10 Sledlengths on identical sleds based on our basic testing.

    it shifts up and down like a dream and drops rotating mass..  Best, if not only Mod we are seeing on late Model hotrodder sleds.
    Is that Team Industries?  I'm sure it is acceleration gains, but gives up a lack of top end, right?


    MotoJ


      "zerogravity!"

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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #6 on: February 26, 2014, 01:38:52 PM »
  • Is that Team Industries?  I'm sure it is acceleration gains, but gives up a lack of top end, right?

    my understanding is you don't really lose top.. you just get there quicker


    btw top-end isn't anmything anyone is going for anymore.   The days of the HO triples pulling 130MPH are behind us.

    T-CAT


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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #7 on: February 26, 2014, 07:23:00 PM »
  • my understanding is you don't really lose top.. you just get there quicker


    btw top-end isn't anmything anyone is going for anymore.   The days of the HO triples pulling 130MPH are behind us.

    True! I could care less that my sled tops around 95, but the way mine is clutched i can take 600's oit of the hole if i get hooked up

    vince




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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #8 on: February 26, 2014, 07:55:29 PM »
  • True the gearing doesn't change it is more like how fast you up shift and down shift.
    And for me top end does mean a lot. When you have lots of top end you have lots of power. And every time you are on a lake your going for that top end.
    2015 YZFR1 Yamaha Raven
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    Black flag me if you want, catch me if you can.
    I bought it to ride. Not to look at.

    T-CAT


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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #9 on: February 26, 2014, 08:07:48 PM »
  • True the gearing doesn't change it is more like how fast you up shift and down shift.
    And for me top end does mean a lot. When you have lots of top end you have lots of power. And every time you are on a lake your going for that top end.

    I'm not a lake racer, i like ditch hopping so a sled thats light and able to hang skis is important to me

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    Bear


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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #10 on: February 26, 2014, 11:50:59 PM »
  • I'm not a lake racer, i like ditch hopping so a sled thats light and able to hang skis is important to me

    Same here :thumbup:


    Im not kidding our normal group would have mentally devastated this girl. Im talking years of therapy to even be able to tie her shoes again. She was nice enough girl but she was in over her head.

    vince




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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #11 on: February 27, 2014, 12:35:10 AM »
  • Ditch bangers top out at about 40 mph and they don't need a lot of power. Now a trail rider, well that is a whole new game.

    636



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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #12 on: February 27, 2014, 03:02:07 AM »
  • Is that Team Industries?  I'm sure it is acceleration gains, but gives up a lack of top end, right?



    Changing clutch weights and helix profiles have ZERO effect on overall top-end speed.

    Clutch weights are in the primary.  The overall clutch weight needs to be tailor matched to achieve full shift-out at the exact RPM that your motor peaks HP.  If it shifts-out to early or late... you're leaving some performance on the table.  Too much weight, your sled won't be able to spin the primary fast enough to achieve full shift-out.  Too light, you'll over shoot the peak HP of the motor.  Modern clutch weights can even use weighted rivets to move the weight in and out... basically achieving the weight of a 78gram, with the actual rotating mass of a 66gram.

    Once the primary puts the squeeze on the belt, the secondary comes into play.  Here, the ramp angle found on the helix is what determines how quickly the clutch up-shifts AND down-shifts from low to high range, and from high to low.  Angles can be constant, or progressive.  It starts out as a 66*, but then steepens into a 70*.  Think of it as an automatic transmission in a car.  How short is your gear?  A tall gear takes a long time to accelerate through, and uses a broad powerband.  the result is slower acceleration, but very smooth.  A short gear keeps you in a more narrow, more powerful powerband.  More shifts required, but quicker acceleration.  Automatically downshifts quicker and to a lower gear for quicker acceleration once you get back on the throttle.  That's exactly what a helix with a steep profile will do. Let off the gas, your sled backshifts so quickly it almost sends you over the handlebars.  Has you in a "low gear" ready to hit the throttle and scream out of the corner.

    The true function of a sleds acceleration is due to its power output, and final gearing.  To use a visual, consider the gearing of your sled to be a ladder.  A snocross sled will have a short 6 foot ladder, topping out around 80ish.  A 90's triple lake racer could have 20 foot ladder topping out at 125mph.  The snocross sled will only get to 80 despite having almost as much power as the lake racer, it will just get there much much quicker.  That is all due to HP and gear ratio.  Where CLUTCHING comes in... is how quickly the dude on the ladder can climb up and down.  A shallow helix angle will keep that dude climbing up and down at a respectable rate, and be very steady and sure footed (smooth).  A steep helix angle will have him climbing up the ladder at a faster rate... but much more noticeable is the fact that when he is at the top and you let off the gas, he will INSTANTLY drop down that ladder like a Navy sailor sliding down rather than stepping down.  Now when you get back on the gas, he's already at the right height of the ladder... you're not waiting for a slower climber to finish climbing down before starting his way back up again.

    The most important things in snowmobile clutching are: Proper alignment, belt clearances, and cleanliness.  Without these, you'll have all kinds of inefficiency, and potentially a ton of belt wear.  A powerful sled can chew up and spit out a $150 belt like nothing.  I've blown several at 110+mph.  It felt and sounded like the engine grenaded. Bent the belt guard, reached down and grabbed the speedo cable and wrapped it around my primary.  They often destroy the belly pan and hood as well.  Alignment and tolerances are set "close" at the factory, and the dealers are instructed to fine-set them during dealer prep.  This usually does not happen.  HUGE performance gains from identical new sleds just from taking a few minutes to set them up right.  Oh, and always break the sled's track free of the ground by lifting it up before driving  (or you'll glaze / smoke the belt)... and take it easy the first few miles to let the belt warm up.  Cold belts don't like 160hp 78gram weights, and 76* ramp angles.

    So, that's probably enough rambling off the top of my head.

    Good Luck with your Polaris interview.  It's a great company to work for.  It's extremely hard to get in, they only take the top of the top in their respective industries... it's not a company that gives young guys a chance to prove themselves in a step up from their current positions.  They like 15-20 years of proven performance doing exactly what they are hiring for. 

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    DVS_DAN


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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #13 on: February 27, 2014, 09:11:05 AM »
  • Awesome write-up, thanks man  :handclap:

    MotoJ


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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #14 on: February 27, 2014, 09:18:55 AM »
  • BUT...


    DOES IT WHEELIE?

    :idk:

    636



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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #15 on: February 27, 2014, 10:03:39 AM »
  • BUT...


    DOES IT WHEELIE?

    :idk:

    Nope, neither my Ultra nor Pro-X wheelied.  You want to set your weight transfer so the skis get light under heavy acceleration, but don't come fully off the ground.  You'll lose your ability to steer out of the corner, and you'll start to loose contact patch if the wheelie gets very high.

    JUMPING, however, is a different story.  The Pro-x loved the air, she could really launch.  The Ultra not so much.  A tad on the low and heavy side.  She was more like, "I wonder what is on the other side of the lake...NOW." 

    MotoJ


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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #16 on: February 27, 2014, 10:05:50 AM »
  • Nope, neither my Ultra nor Pro-X wheelied.  You want to set your weight transfer so the skis get light under heavy acceleration, but don't come fully off the ground.  You'll lose your ability to steer out of the corner, and you'll start to loose contact patch if the wheelie gets very high.

    JUMPING, however, is a different story.  The Pro-x loved the air, she could really launch.  The Ultra not so much.  A tad on the low and heavy side.  She was more like, "I wonder what is on the other side of the lake...NOW."


    I had a shot at a Hawk Racing SRX This winter... Wish I could have grabbed it... it would suck in ditches but holy crap the speeeeeeed!


    636



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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #17 on: February 27, 2014, 10:16:36 AM »

  • I had a shot at a Hawk Racing SRX This winter... Wish I could have grabbed it... it would suck in ditches but holy crap the speeeeeeed!



    A HAUCK Racing SRX???  Yeah, she'd go in a straight line on a smooth surface in a hurry.

    MotoJ


      "zerogravity!"

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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #18 on: February 27, 2014, 10:20:14 AM »
  • Bubba almost traded me straight up for my gixxer lol.


    The sled was so clean.. so nasty!

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    Bear


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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #19 on: February 27, 2014, 12:31:45 PM »
  • Bubba almost traded me straight up for my gixxer lol. The sled was so clean.. so nasty!
    That yamaha "drag sled" he had? :idk:

    MotoJ


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    Re: How does clutching work? Springs, helix, weights, etc...
    « Reply #20 on: February 27, 2014, 12:34:11 PM »
  • That yamaha "drag sled" he had? :idk:


    yep, he blew the top-end,  got some parts from us, rebuilt it, lowered compression a hair to avoid the racegas needs, it was Gnar Gnar.


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