Sportster crank bearings

Discussion in 'Road Warriors' started by Sonicbooms, Feb 28, 2018.

  1. TxRoadDog

    TxRoadDog Shut up and ride

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    You basically just proved me right, but ok. Every rigid mount Harley I built has been smoother at highway speeds than my Inline 4's. I guess I just don't know what the fuck I'm doing?
    May be the difference between a builder and a garage gear head. :dunno
    #41
  2. Mattbastard

    Mattbastard Lazy ass

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    No, it just shows that you have a higher tolerance for vibrations than others.

    What balance factor do you use on your crankshafts?
    #42
  3. TheProphet

    TheProphet Retired; Living the Dream

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    #43
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  4. mojave

    mojave Been here awhile

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    Right

    For ENDLESS discussion on this subject, literally decades of it, go to the XLforum.net. Real experts to blowhards. Raging flame wars that lasted years. Colorful personalities, assholes, wisemen,wiseguys. It's all there. At least it was 6 or 7 years ago when I sold my Sportster and stopped reading it. By then the rigid frame bikes were fading into the past as most people recognized the overall superiority of the rubber mounted bikes.

    And by that time my humble XL883/1200R had become the longest kept bike I've ever owned, but it was getting to be an old burned out relationship.

    BTW, there is an analog to this that I know a lot about. I'm an optical designer, I design everything from complex high energy laser trains and directors to simple radiometric devices. I know the optical theory from both formal grad classes and 35 years of professional experience. In short, I'm an expert doer. Anyway, the achromatic telescope objective, which was invented ~ 200 years ago, is intrinsically inflicted with residual color aberrations called secondary chromatic aberration and secondary color. The way you mitigate the deleterious effect of these aberrations is to increase the focal ratio (F-number), that's why old refracting telescopes are so long. This is kind of like running a primitive unbalanced engine (e.g. Sportster Evo!) slowly - the vibration is there but the felt force and mechanical amplitude is low because the velocity of the vibration is low (if you will, I'm not an expert on vibration). In the objective lens case the color aberration becomes small relative to the depth of (sharp) focus as the F-number increases (in case you were wondering). There are endless discussions and claims stretching back hundreds of years (!) about how to balance and diminish or fix color aberrations. 99 percent of the discussion is not based on anything but faulty understanding, and most is driven by ego. If anybody would actually learn the theory, do the raytracing or aberration calculations, they would realize the futility of trying to "fix" this defect by juggling the primary lens components of the objective - this is akin to balancing an engine via the crank/rod/pistons. Oddly, there is a final analog element to this. Any student of physics, and maybe a mechanical engineer that is zanier than most, would suggest that you can apply a counterbalancer to the Sportster engine and more or less fix it. Been tried a few different ways with minor or no success. Optically, a different story. It is not that hard to design a near focal plane "corrector" to put those colors back where they belong. Coming up with the glass with very abnormal optical properties is hard, but leave that to the vodka fueled eggheads in the former Soviet Union. Making and marketing such a device was done, and to my amazement, it worked. Kind of. That's some optical heavy lifting going on and there are serious issues with maintaining alignment. I actually owned and used one of these "Chromacorrs" for a couple years but finally decided I liked the simplicity of my always perfectly aligned 8" F14 objective all by itself. Even if it does have a terrific purple halo around bright objects. In the meantime the Chormacorr, of which I think only 500 were made, was out of production never to come back, I had no problem selling mine.
    #44
  5. Mattbastard

    Mattbastard Lazy ass

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    My build is probably still on XL Forum, although all the Photobucket pics are probably shot by now.

    I just get a little butthurt when someone spouts about how smooth the rigidmounts are when I was actually a victim of those damn paint mixers based on multiple people's feedback claiming the vibrations were "not that bad"... Sure, you take a bike on the designated dealership route and you never hit the vibey speeds but once broken in and you stretch her legs its numb hands before you hit your first piss stop and everything in the mirrors looks like a Jackson Pollock painting.

    Edit: All that shit being said, that Sportster was my longest owned motorcycle for some damn reason. I always had a supplemental bike along side of it but that bike just seemed to always stick around. Maybe it was because of how much I liked working on bikes. Now I have a 1994 Bagger that I'm building an 106" motor for. At least that's rubber mounted.
    #45
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  6. Kevm

    Kevm Eternal Optimist

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    Vibrations....

    ... Yeah some don't mind em as much. And some claim you can get a "balanced" one.

    Generally that's hogwash.

    Harley didn't spend the millions they did redesigning em in there was a way to just balance them (other than a counterbalancer which I've come to argue might have been a better solution).

    But I've seen solidmounts split their oil tanks, shake bulb filaments apart, drop fasteners from peg mounts to engine mounts, even split license plates in two.

    For the type of generally longer distance riding I prefer I probably wouldn't ever own a solidmount again... Unless they redesigned em like the FX M8s, but that's another story.
    #46
  7. Ginger Beard

    Ginger Beard Instagram @oneworldcycles

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    This right here is why it's always important to take extended test rides. 10 people could ride a bike and you'd wind up with 10 opinions. I'm in the "not that bad " camp, so much so that the slightly smoother at highway speed 09' wasn't enough to overcome the weight penalty. I kept the 01' which just rolled over 80k miles this past week.

    I'm with kevm in that I hope the next gen Sportster is counterbalanced . Would be nice to see the weight come back down to pre rubber mount specs.
    #47
  8. Ginger Beard

    Ginger Beard Instagram @oneworldcycles

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    You should ride one. The DR650 vibrates differently (smoother and more consistently throughout the rev range) . To some , the Sportster's vibes are a deal breaker while to others it's a non issue. Only you as a rider can really make that decision.
    #48
  9. ronandkat

    ronandkat Been here awhile

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    Just traded a 2014 versys for an FJR in November..A large part of the reason was an annoying as hell Vibration. It's ridiculous this day and age to have any modern bike produce enough vibration to be annoying and have you searching for fixes. My 07 Uly, was Buttery smooth. Except at Idle, but thats a different beast.
    #49
  10. Mattbastard

    Mattbastard Lazy ass

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    That's because Buell was smart enough to know to rubber mount all his bikes that came with Sportster engines. I'm not sure about the Rotax engined ones though.
    #50