Rubber Mount vs Balanced Crank Shaft

Discussion in 'General Harley Davidson Topic' started by RumbleRoads, Oct 30, 2007.

  1. RumbleRoads

    RumbleRoads Member

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    Rubber Mount vs Balanced Crank Shaft

    Witch do you like? I have a 05 Heritage Softail Classic and been thinking of getting a new Road King Classic. I had never before the experience of riding both kinds of Harleys before. I got to test ride an 08 RKC and like the ride a lot. I would not say it rides better than my Heritage only different.

    It was much smother and handle more stable than my Heritage and at 55 there was no engine vibration at all that I could feel at 55 and above. I have heard some riders say they did not like or could not stand the engine vibration of the rubber mount engine on the Road Kings. I like the feel or the Rubber mount engine. Years ago I had an old Yamaha that vibrated so bad it made my hands go so sleep. The kick of the RK V-Twin felt good to me, the vibration was mild compared to the old bikes and did not ever bother me a bit.

    My Heritage has very low vibration at idle and I get more vibration increasing as speed increases passed 55. But the stock riding positions is very comfortable for me. On a side note the Road King’s passenger’s floorboards will clip my shot legs if I’m not careful when parking or slow maneuvering. This is not a problem just something different than with my Heritage that I had to adjust too.

    One other thing, my first ride on the Road King Classic was solo and when my wife hoped on for the 2nd ride I could not even tell she was on the bike. I can tell a difference in the way my Heritage handles when she rides with me. The Road King was the first bike I ever road that seemed to handle just as well riding solo or with a passenger. But my Heritage has that old bike style I love so much.

    What do you like? Rubber Mount or Balanced Crank Shaft?

    I like them both but only thinking about a Touring Harley because of the added benefits in the design for long trips.

     
    Last edited: Oct 30, 2007
  2. glider

    glider Veteran Member

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    They both have their unique features. The RK vibrates a bit more at idle because of the longer stroke in the 96 engine than previous years but how much time do you spend at idle compared to cruising. The soft tail buzzes at road speeds of about 55 even thou they are balanced. The older unbalanced soft tails were much worse, they would actually vibrate your feet off the pegs.

    I had the same problem with the rear boards clipping my legs during maneuvering so I opted to go with a set of pegs and used the chrome mounts that come standard on the street glide and it works for me now very well. Much easier on the maintenance where you don't have to remove the passenger board to get to the clutch or to service the primary.

    Overall I would go with the RKC again over the softail in the future for the ride and overall comfort.
     
  3. Not Very PC

    Not Very PC R.I.P

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    Rubber is smother and a properly trued engine in rubber mounts is a sweet thing indeed! Even a built 103 won't put your feet or hands to sleep.
    B motors are limited to around 6500rpm as well if you have engine mods planed for the future. Even the B motor 6 speeeds buzz at highway speed 55-65mph.
     
  4. iam499b

    iam499b New Member

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    I just picked up a used '01 RK (5,800 miles on it) last week. I still have an '05 Softail Deluxe (88B w/ 13K miles on it). I've noticed that at a traffic light or other idling situations, the RK engine has noticeable shaking, compared to my Softail, which is very smooth at idle up through freeway speeds. As soon as I accelerate, the engine vibration smooths out to the point where it's unnoticeable. At freeway speeds, it is silky smooth.

    Both engines run Mobil 1 fluids; 20W50 in the crankcase, 10W40 4T in the primary, and 75W90 gear oil in the tranny.
     
  5. acerider_01

    acerider_01 Member

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    I think both styles were designed for different purposes and what you intend to do with the bike should help determine the end choice. Softail is lighter, more performance oriented bike and touring bikes are for spending time on highway with or without passenger and luggage for the trip. I chose the StreetGlide because I wanted to be able to make long trips mainly but, now I find my self riding to work daily, grocery trips, whatever! I guess if vibration at idle bothered me too much I could hold throttle and keep engine off-idle?
     
  6. Not Very PC

    Not Very PC R.I.P

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  7. glider

    glider Veteran Member

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    Agreed, I had a softail that was 722 wet 763 in running order. My RK is only 732 lbs dry.

    Even the heritage is 750 lbs in running order.
     
    Last edited: Nov 2, 2007
  8. DYNAGUY

    DYNAGUY Active Member

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    I like the rubber mount. Got that harley shake at idle.Smooth as glass at road speed.
     
  9. zyepod

    zyepod Active Member

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    Why are the RK, EG etc. set to shake at idle. Is it a style Harley is after. What if they balanced the crank shaft. Wouldn't it be even smoother with the rubber mounts as well?
     
  10. glider

    glider Veteran Member

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    They shake at idle because the baggers are not counter balanced and the size of the pistons will cause them to shake quite a bit as they run plus the fact they are rubber mounted as opposed to solid mounted with counter balancers like in the softail models.