In The Shop: Upgraded Primary Chain Adjuster

Aftermarket Upgrade

Its been no secret that there has been a serious issue with the 2007 and later Big Twin compensator assembly. We released our Baker Compensator upgrade videos years ago where we demonstrate the installation procedure.

In 2007 (2006 Dyna), Harley seemed to resolve the cam chain tensioner issue only to replace it with a new issue on the opposite side of the crank. The factory compensator assembly had a weak spring pack and poor lubrication which, in turn, created hard starts and a “clunking” noise from inside the primary drive case.

Baker suggests using their Armored Attitude Adjuster to go along with the compensator assembly upgrade. This is not just shameless upselling on Baker’s behalf. Harley’s automatic primary chain tensioner has issues of its own. At the first movement that the chain has slack, the auto tensioner ratchets the shoe up another notch. One notch may not be an issue but the auto tensioner can only adjust in one direction; tighter.

Now, it is not uncommon for the chain to have slightly excessive slack for a only a fraction of a second. When this happens, the auto tensioner over compensates and locks into a tighter position that leaves the chain tension extremely tight. When this happens, it creates excessive stress on the primary drive, and transmission main-shaft. In turn, the heavy pull on the transmission main-shaft wipes out the inner primary bearing and race. If this is not addressed, the compromised shaft support will eventually wipe out the transmission main bearing, the transmission door bearings, or both.

Recently, In The Shop, we had a 2010 FLHTCU come in that had been experiencing hard starts which was not addressed soon enough and ultimately turned into hard, grinding starts. We replaced the starter Bendix gear, the starter ring gear, & primary chain. We upgraded and installed Baker’s compensator assembly and “Attitude” primary chain adjuster and filled the primary compartment with Spectro heavy duty primary oil. For those of us with older Twin Cams and Evos we can still adjust the tensioner, see here.

As long as this bike has a healthy battery, it may never experience another mechanical starting issue.

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9 Responses to “In The Shop: Upgraded Primary Chain Adjuster”
  1. Colin Manion
    Colin Manion

    I have a 2010 Road King, I believe it is the 2011 model, it has the 103 motor. Just had a service done at 65000 km’s, about 40000 miles and was told my Compensator was needing attention soon. I never knew what a compensator was so started looking. So I have the choice of Baker, Screaming Eagle or HD. So I rang HD and of course they said that the new HD that would be fitted to mine was as good as anything else and would be cheaper, not to worried about the price, I believe in buying what it the best…you get what you pay for. My question is from someone who is not a HD Mechanic or dealer, What is the best and why and do I just replace the compensator or is there other stuff to do. I basically just have a Standard 103 that was given the Screaming Eagle Stage 1 upgrade when I bought it pipes, aircleaner etc, no engine upgrade with Cams etc

    • DC Smitty
      DC Smitty

      Colin, you did not mention why your mech says why the compensator was “needing attention soon.” Is it starting hard or clunking as the article describes? If yes then it should be replaced. I purchased a used 13 Road King and mine developed the clunking sound when shutting off only after the motor was good and hot. So I replaced mine. We know the stock H-D part is junk, don’t want that. Heard on blogs that H-D Screamin Eagle part is only slightly better so I went with the Baker unit and 7000 mi later still no clunk. Also replaced primary chain tensioner with non-ratcheting type similar to the Baker “Attitude” adjuster. Best of luck,

  2. Payton

    I’ve ran into this issue on my 08 Street glide. Had to replace main shaft and bearings. I’m glad to see that a old style system will still work with no problems.

    • Matt bruce
      Matt bruce

      I’m working on a 2004 harley davidson electraglide does anyone know the size of the bolts that hold the primary chain tensioner on. His bolts came loose and broke his chain but I can’t find the replacement bolts

  3. Thomas Machen
    Thomas Machen

    I recently had my stator rotor and voltage regulator replaced along with my starter clutch and compensator and now when I turn my bike off I can hear like a rolling sound on my primary side just for a second like something keeps turning after I shut it off…is that normal??? Also what do u guys think about the compensator eliminator??? I’m seriously thinking about going that rout??? Oh yeah btw my bike is a 2008 soft tail night train fxstb


    Hi Kenneth I talked to you guy’s awhile back about my old 07 street glide the grinding noise it was making when you let the clutch out and wouldn’t move belt was wiped out when clutch was let out it would grind like a starter on a car was still engaged or stuck between 2 gears when I drained Prim. & Trans no metal and drain plugs good. After taking it apart and looking at the and the bearings bearings felt good the main drive 5th gear Prim. bearing and race the trans main were clean no pitting race had not walked but you could see wear chain had rub’ed along side of inner prim. and the bottom bolt hump the compensator and in front of the clutch assy. starter ring from top to bottom flipped it and a few of to inside spilnes were about 1/32nd in bearing felt good and looked good so I slid the 2 assy. back on the bike took a straight edge laid it against chain side gear on clutch assy. then to comp and it lined up so while prim. was I looked see if the clutch hub was riding on the main shaft bearing race or hitting trans main shaft seal each had weren’t turned and grabbed the starter ring and then up and down side to side turn it no move meant or rough feeling in it so I was going replace all the bearings on side and seals on that side and look at the inside of the basket I have the clutch disc and out don’t see any cracks out side/inside I am going to to put a manual chain adjuster on it was planing to go with Baker and I have a few friends with shops they told me that Baker was junk my buddy that did eng. up grade was one of he did the eng. about 45 thousand 106 hp 101 foot lbs of torque or the way around can you put some insight on this when I was a mech. I know well have the parts that don’t hold up I will tack any advice you can give don’t any longer so don’t the funds I’m used to but I don’t believe in half ass doing the job do it right

    • Customer Service
      Customer Service


      We would be interested to know why your friends say that the Baker primary chain adjuster is no good. We prefer them over the stock auto adjuster. Especially for built engines with high torque. The auto adjuster assembly is known to get stuck in a tight position. This not only quickly wears the adjuster shoe, but it also puts a lot of strain on the transmission mainshaft. When that condition exists, it is common to blow bearings. Not just the inner primary bearing. It can wipe out the main bearing &/or transmission door bearings.

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