Automatic Primary Chain Tension Adjuster

Part Number 40063-05B




Original Equipment on '06-later Dyna® and '07-later Softail® and Touring models, this Automatic Primary Chain Adjuster eliminates the need to manually adjust the primary chain tension at traditional service intervals.

  • Requires separate purchase of model-specific primary gasket and seals

Fits '85-'06 Evolution® 1340 (except '85-'88 Softail®) and Twin Cam powertrain. Requires separate purchase of model-specific primary gasket and seals.

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  • Model
  • These Screamin' Eagle® products are 50-state street-legal for sale and use on all vehicles, including those that are pollution controlled. Complies with the requirements of 40 CFR Part 86, subparts E and F.
  • Warranty

    1 year limited warranty – Go to for full details
  • Sold in Unit

  • In The Box

    Chain tensioner and all necessary installation hardware
Auto Primary Chain Tension Adjuster is rated 4.0 out of 5 by 3.
Rated 3 out of 5 by from 2006 Road King Installed on 2006 Road King only thing I don't like if you race your bike in time this will over tighten and you will have to reset it learned that from the dealership, after install your sled will make a new noise that's the chain because with this installed you will go from 5/8 to 3/8 give it 200 miles it will settle down, if you have the viewing port check it every oil change.
Date published: 2017-02-04
Rated 5 out of 5 by from Smoother shifting Instructions were easy to follow and the product was easy to install. Gear shifting became much smoother after product installation. The hard shift into first gear from neutral has been minimized (but not removed altogether). I am very happy with the performance of my 2001 FXSTDI (88 twin cam) following the installation of this hydraulic primary chain tensioner. Currently using HD transmission/primary oil.
Date published: 2015-11-16
Rated 4 out of 5 by from nice unit got this for one less thing i gotta do. sure hope im doin the right thing. check back later and ill tell u da truttth.......ok?
Date published: 2014-08-03
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  • clientName_harleydavidson

will this fit my Dyna Streetbob FXDB 2011?

This chain tensioner looks a little different from the one that was just removed. Different in the color. I believe the mecanism looks the same.
Asked by: BikErick1135
Hi BikErick1135, Try P/N 39929-06B. We do not have this part online, but it does match with the 2011 FXDB. Good Luck!
Answered by: RowdyGrl79
Date published: 2016-09-14

Will this part fit a 2007 Road Glide ?

The fitment list on the main page says it will fit a 2007, but the years given only go as high as 2006. Thanks, Dom
Asked by: Dom22
Hey Dom22, Thanks for your question! This part is actually stock (Original Equipment) on 2007-later Touring models. This is why the fitment only goes up to 2006 fitment tab. Hope that helps!
Answered by: Wisco832
Date published: 2015-10-23
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    Prices listed are generally the Manufacturer's Suggested Retail Price (MSRP), excluding taxes and shipping. Prices at local dealerships may vary. All online orders will be fulfilled and shipped by
    Harley-Davidson Motor Company as the agent for the Selling Dealer.