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REF: Primary Drive & Clutch


Clutch Parts & Mods - Aftermarket


91 and Later Aftermarket Clutch Packs

Energy One

BTX-11:
9 Kevlar friction plates, 8 steel plates plus a 15% stronger diaphragm spring. 1)
Recommended fluid type:
The use of synthetics is not recommended as they tend to cause slippage. 2)

  • Any HD petroleum based, non-synthetic, primary oil, as light weight as possible.
  • Or even a good petroleum based motor oil such as 10/40 or 20/50 in weight.
  • You can even use ATF Type F or B&M Trickshift.

Installation:
Start with a friction plate and end with a friction plate. 3)
The OEM rivet plate is discarded and not used with this kit.
This kit includes 1 extra friction and steel plate to retain the OEM stack height.

Energy One BTX-11 4) Soaking the plates in oil 5)


Screamin' Eagle® Performance Clutch Kit

HD has a Performance Clutch Kit (Number 38002-04) designed to fit 1991 and later XL and 1994 to 1997 1340 Evolution® model motorcycles.6) This kit is still being sold by HD as of 12-22-2016.

  • The nine high performance friction discs and eight spacer discs in this kit replace the original eight paper friction discs and six spacer discs. This kit also replaces the spring plate and diaphragm spring with a higher rate diaphragm spring.7)
  • Cautions: Do not reinstall the OE spring plate and diaphragm spring with this kit. Doing so will affect the stacked height of the clutch discs. The spacer discs supplied in this kit must be used with the high performance friction discs. Do not use the original equipment (OE) spacer discs with this kit. Doing so will affect the stacked height of the clutch discs, resulting in clutch slippage.
  • Installation, refer to the applicable Harley-Davidson Service Manual for installation of friction discs, spacer discs, and diaphragm spring in kit, but follow these important guidelines:
    • Remove the original eight friction discs, six spacer discs, spring plate, and diaphragm spring from the clutch assembly as described in the Service Manual, and discard.
    • Replace with nine high performance friction discs, eight spacer discs, and diaphragm spring from kit. Place a friction disc into the clutch shell first, then alternate spacer discs and friction discs.
    • Kit includes:
      • Disc set including 9 friction and 8 spacer discs. Part #(38001-04)
      • 1 Spring, clutch diaphragm Part #(37949-98A)


Barnett Kevlar Clutch Kit

In this section, Grind, from the XLForum.net, notes that he had ordered a new Barnett Kevlar clutch pack & Barnett 25% stronger diaphragm spring for his 2004 1200C Sportster. The pictures below are from that thread: 8)

These are the instructions that came with the kit:

This Barnett Kit still came with the Judder Plate (which Barnett no longer uses):

Below, on the left, is a comparison of the Stock Diaphragm Spring (Top) & the Barnett 25% upgrade spring (Bottom).
On the right is a comparison of four brands of Friction Plates. Top to Bottom is: Stock HD, Energy One Kevlar, Alto Carbonite & Barnett Kevlar:


Upgrade Clutch Diaphragm Springs - Pressure

Below are a list of upgrade versions. The 'xx% stronger' are claimed values by the respective vendors. Energy One suggests that if you are using a diaphragm spring of +25% that you should also upgrade your pressure plate to a billet version because they have had issues with the stock cast pressure plate cracking. 9)

L1984-90 Sportster

Barnett Scorpion Clutch Kit 607-30-10084 10)

  • MT-33-6 - - - 396lbs (six springs)
  • MT-112-6 - - 420lbs (six springs)
  • MT-113-6 - - 480lbs (six springs)

1991-later Sportsters

Screamin’ Eagle HD-style Clutch Spring 11)

  • 350lbs - 10% Stronger Than Stock 1200 Clutch Spring (SE Clutch Spring 37949-98A)

Energy One HD-style Clutch Spring 12)

  • 340lbs - 15% Stronger Than Stock 1200 Clutch Spring (BT15) (% based on '91-'03 1200 OEM spring)
  • 380lbs - 25% Stronger Than Stock 1200 Clutch Spring (BT25) (% based on '91-'03 1200 OEM spring)

Barnett HD-style Clutch Spring 13)

  • 360lbs MT-81 - 10% Stronger Than Stock 1200 Clutch Spring (502-00-01081)
  • 400lbs MT-77 - 25% Stronger Than Stock 1200 Clutch Spring (502-00-01077)

Barnett Scorpion Clutch Kit 607-30-10091 14)

  • MT-18-6 - - - 348lbs (six springs)
  • MT-112-6 - - 420lbs (six springs)
  • MT-113-6 - - 480lbs (six springs)

These springs can be mixed such as: 15)

  • 3x MT-18 plus 3x MT-112 = 384 lbs
  • 3x MT-18 plus 3x MT-113 = 414 lbs
  • 3x MT-112 plus 3x MT-113 = 450 lbs

AIM Corp. sells Diaphragm Springs (made by Energy One):16)

  • 150lbs - AM006-150
  • 190lbs - AM006-190
  • 240lbs - AM006-240
  • 320lbs - AM006-320
  • 400lbs - AM006-400
  • 480lbs - AM006-480
E1 Claims 400lbs is the max pressure version they make. As shown below,
the AIM 480lbs version & the E1 400lbs version may be the same product.

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'91-later Alternative Clutch Pack Using XR1200 Parts

This discussion regards using some of the clutch parts found in the XR1200 model in place of the stock XL model design. This XR parts usage was initially explored due to some issues that occur after the XL Spring Plate is replaced with an aftermarket 'Extra Plate Kit' or when adding 2 stock steels & a friction. Sometimes those alternatives will 1) have an abrupt grabbing (lurching) on clutch engagement and/or 2) produce an unpleasant squeel. Using the XR parts instead of the XL Spring Plate is said to eliminate those issues.

These are the XLForum threads related to this alternative: (Thanks to Bluto for pioneering this alternative):

http://xlforum.net/forums/showthread.php?t=2044017
http://xlforum.net/forums/showthread.php?t=2072418
http://xlforum.net/forums/showthread.php?t=2074994

Here's the pictures Bluto posted of the parts:

In both designs, the clutch pack is a combination of friction plates and steel plates that are sandwiched together between the base of the clutch hub and the pressure plate. In the stock XL design, there are 8 friction plates, 6 steel plates & one spring plate (see below).

The XR1200 model was offered between 2008 & 2013. The clutch design in this model uses springs built into the clutch hub along with a bevelled spring plate (known as a Judder Plate) to absorb clutch engagement forces. The XL models also use a spring plate, but it consists of two metal plates that are connected with spring leafs that are riveted in place. This XL spring plate, especially in the rubbermount models, has failed quite often by the rivets sheering. Most often, the clutch basket is scarred. This requires careful filing to remove the raised areas on the damaged clutch basket so that the friction & steel plates can move back and forth smoothly.

The XR1200 clutch basket is not a drop in replacement for the XL design but the Judder Plate portion of that design will fit into the stock XL basket. In this implementation, the XL spring plate, subject to many failures, is removed. In this XL alternative configuration, there is the Judder Plate plus 8 friction plates and 8 steel plates.

The components that make up the Judder Plate design are a 'narrow' friction plate, a bevelled spring plate and a spring seat plate. The inner diameter of the friction plate is larger than a normal friction plate (thus making its radial thickness 'narrow'). Both the spring & spring seat (which have the same smaller outside diameter) fit inside the diameter of the 'narrow' friction plate. This makes the combined components equivalent to one friction plate.

These components are placed in this order in the bottom of the clutch hub (first pieces to be installed) - Narrow Friction Plate, Spring Seat and Bevelled Spring Plate. Next is placed a Steel Plate, followed in succession by a Friction then Steel Plate until all plates are installed.

As regards the bevelled spring, the inside diameter should sit closer to the Hub Base and the outside diameter should sit closer to the Pressure Plate.

NOTE-1: With the Judder design, which requires additional motion in the clutch compression process, I would expect it to be more difficult to get the correct setting of the adjustment screw (perfectly balanced) to allow enough motion for the plates to get from fully engaged to fully disengaged. Pay close attention when you make the clutch adjustment of the ball & ramp assembly so that the clutch plates will move sufficiently.

(Note of Caution: This configuration is a new experiment - implement it as you see fit. Additional notes will be added as more experiences are related on the XLForum regarding the success.)

XR Parts to Replace Stock XL Spring Plate
- - - - - - - - - - - - - - - - - - - - -
37894-02 Judder Spring
37895-02 Judder Spring Seat
37897-02 Friction Clutch Plate - Narrow

Extra Steel Plates (2ea)
37913-90 Steel Clutch Plate



Upgrade Clutch Release Bearing - HD P/N 8885 to 7200B Angular Ball Bearing

You might consider replacing the stock bearing, P/N 8885, which is a standard ball type bearing (equiv. to 6200). Using an angular contact bearing, which provides additional support in the axial direction, is a better alternative for this application. The upgraded replacement would be FAG 7200B (not available from HD) and is an angular contact bearing. Thus, it is important to orient the bearing in the right direction when pressing the bearing into the Release Plate. Be sure to purchase the genuine FAG brand or another high quality bearing (as knockoff versions do not hold up).

The wide side of the 7200B outer bearing race should be placed into the release plate first. This also means that the narrow part of the inner bearing race is first into the plate.

When correctly assembled, the narrow part of the outer race and the wide part of the inner race will each be exposed on the insertion side of the release plate. The Adjustment Screw is inserted into that wide side of the inner race, as shown below.

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Additional discussion: http://xlforum.net/forums/showthread.php?t=1688139


Muller Power Clutch - Release Assembly

The Muller Power Clutch is a replacement for the stock Ball & Ramp Clutch Release Assembly. It consists of a front & rear plate with 3 ball bearings between the plates (similar to the stock version). The Power Clutch version has wider ramps, smaller ball bearings and the arm (to which the cable attaches) is longer.

These changes provide a longer, but easier, pull on the clutch lever to activate the release of the clutch plates. This product is often added when a stronger clutch diaphragm spring is chosen to help keep the clutch from slipping when a power upgrade to the engine has been installed.

There have been some complaints that the total pull of the clutch lever (when used with the Muller Power Clutch -and- using a very heavy pressure diaphragm spring) is not sufficient to properly adjust the clutch release. Either the clutch plates drag at one end of the adjustment or they slip at the other end of the adjustment because of the motion required by the very heavy spring.

The typical retail price for the Muller Power Clutch is $180.

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