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Screamin Eagle Big Twin Compensator

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  #21  
Old 10-15-2008, 03:27 PM
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Originally Posted by GAstreetglide
It's been over a year since I last had my primary apart. But if my memory still serves me correctly, it seems like the ramp angles are steeper and each section is physically separated by a barrier. It also appears the spring/diaphragm pack is much beefier. I’ll know for sure in a couple days. Keep me posted when you get yours installed.
That's the ticket, steeper ramp angles. Stock unit is seriously shallow requiring way more pressure than is available. Area in spring pack is too small to achieve the pressure while maintaining cam travel with that big mother of a sprocket. Makes it hopeless in function due to design limitations.
Ron
 
  #22  
Old 10-17-2008, 08:42 AM
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Originally Posted by GAstreetglide
It looks like a replacement for the existing crank bearing. There's not enough room to install or support a second bearing. This appears to be just one more example of a poor or weak design that we can now correct at our own expense. Nevermind you likely spent $20,000.00 or more for your bike, just consider that HD has now given you the opportunity to make it much better. I'd likely go with the Timken bearing conversion just for spite.
Thats what I figured. Useless then. If your going to spend the time and labor to replace that bearing, the Timken is the only way to go.
 
  #23  
Old 10-17-2008, 01:49 PM
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Lets say you had the lefty brg installed with a crank with an unknown runout?? This brg setup could make things worse!
 
  #24  
Old 10-17-2008, 03:29 PM
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I agree. Timpkins can't even work well if the runout is extreme. Straight may actually , while not good for the outer edges may cause less problems down the road. With a straight crank, no question tapered timpkins best way to go.
Ron
 
  #25  
Old 10-18-2008, 10:30 AM
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Just picked up my compensator. As promised I gave it a look over and have to say once you look at the spring pack and compare it to the original, you will burst into laughter looking at the original spring pack. The new one is progressive meaning that the cruise should have cushioning but where the new on shines is it will have cushioning on higher load conditions as well. The original spring pack is a fixed pressure from from it's wimpy initial 1/3 rd compression all the way to bottoming out. Disc spring dynamics is that stacked in series 4 have the same pressure as one, but travel is increased with stacking. On the new comp there are two big mothers in series, two medium mothers in series and one wimpy one about the size of the original comp spring for light loads. This gives a progressive effect within the compression range, while not a straight line increase in pressure it way better than a fixed rate. I give it my two greasy thumbs up It does not fit 2008 FXCW/C Rocker or 2009 FXSTSSE3 softail springer.
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Last edited by rbabos; 10-18-2008 at 10:33 AM.
  #26  
Old 10-18-2008, 10:43 AM
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Hey Ron, nice review.. thanks for that!

I wonder what was the MoCo's motivation for the stock design. There was a reason for using it that doesn't include screwing customers. Serious businesses like HD that have been around for a century didn't succeed by developing inferior products unless they're chasing buyers who are focused almost solely on price, and that ain't the HD market.

As a former product manager, I presume there's either a good reason for the stock unit being as it is, or there was some serious political BS going on within the design team that resulted in a known inferior product being produced against the strong opposition of mechanical engineers on the team. It's usually a combination of the two, and it's usually driven by design / production cost or the need to meet project schedule deadline. If this part is creating as big a problem as this thread would suggest, then I guarantee you some heads have rolled within the team.
 
  #27  
Old 10-18-2008, 01:29 PM
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The way I look at it is an oversight in design. Two factors come into play with this stock unit that make it marginal in function. One is the harder hitting long stroke coupled with riding the bike like the old days with low rpms and a gear too high. The second is the large 34 tooth sprocket that has some major mechanical advantage against the spring pack. Put the two together and the comp is basically only good for light load cruising at best. My oem unit did not even have the required spring preload as suggested by disc spring designers. The design was incapable of providing it. The clearance is taken up and that's about it. If you happen to have one where all the clearances go against you, it will be a sloppy rattling unit as was my case originally. If it (preload) was followed in assembly of the unit there would not be sufficient travel in the unit to do it's intended job. By welding a cup on the rotor to retain the discs they could not change the spring pack to anything but what it is now. New unit is all external springs and it comes with a new rotor with the cup missing. The stock unit at rest places the cam tips (small area) into the ramp pockets of the gear. Any wear here and you've lost some initial spring load and there's not enough to start with as it's in the area of only .035 loading. The new unit places this at the bottom of the cam and is a larger area. Cam tips are not even used. A quick look without actually pulling my stock modified unit off shows the ramp angles to not be that much different with about the same rotation rates or slightly more. Someone thought this one out to do it's intended job as every area that I thought sucked with the original has been changed for the better. While it is marketed as a Heavy Duty SE part it is what should have been on the first 07s. Whether it's called heavy duty or ride enhancement, as in the ids it's a great way to rake in more cash , quiet customers, and fix a screwup at the same time. It truely is amazing.
Ron
 

Last edited by rbabos; 10-18-2008 at 02:03 PM.
  #28  
Old 10-20-2008, 12:58 PM
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The SG comes apart tomorrow and all the new goodies get installed including the new SE compensator. Everything should be back together by Wednesday morning or early afternoon, can’t wait to see how the bike runs and how well the compensator works. Wow, this is just like Christmas in October. I just looked at the new compensator again as we were taking all the new parts out of the boxes. There is no comparison between the old and new compensator. It really makes me wonder why HD would install something as poorly designed as the stock compensator on the 96” motor. I’ll provide more information upon completion of this upgrade.
 
  #29  
Old 10-20-2008, 03:36 PM
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GAstreetglide: The only thing I questioned was the composite washer used for thrust load on the cap. Since it's captured anyway there should be no problem with it that comes to mind. I decided it must be to reduce the drag that the stock one had in rotation, as it seemed to hang up. Seems to be some kind of graphite impregnated high temp plastic of some sort. Another area that receive attention this time around. While the bolt comes with a locking snot on it, I'd still wire brush it off and use red loctite instead.
Ron
 
  #30  
Old 10-20-2008, 06:34 PM
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I typically remove any locking snot from the bolts and apply what ever loctite is required, but thanks for the reminder. I'm really anxious to compair the old and new compensators side-by-side to see the difference. I may just take pictures to show the people on the forum.
 


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