In The Shop: Inner Primary Bearing and Race Failure

A problem that had become increasingly more common since around 2008 is inner primary bearing and bearing race failure. Until this time, bearing and race replacement was more commonly performed as preventive maintenance. In The Shop, we would commonly replace the bearing when performing jobs like belt and pulley replacement, transmission shift arm replacement, or when doing transmission and primary seals.

Diagnosing an Evolution model Harley or an early to mid 2000’s Twin Cam with a bad inner primary bearing was far and few between. Fast forward through a couple of part number changes (and likely Harley Davidson vender changes) and we have issues with a design that previously had no issues. If your primary drive becomes increasingly noisy, you may have a bad inner primary bearing. Especially if you notice the sound changes when pulling in the clutch lever, with rpm changes, or when shifting between neutral and first gear.

To diagnose this condition with certainty, you will need to remove the entire primary drive. When the inner primary case is removed and on the bench, a closer inspection can be made of these parts. If the bearing is bad, the bearing pins may look worn or discolored. However, there may not be a distinctive, clear indication that the bearing itself is bad. On the other hand, if the race is no good, it will be be obvious. The surface of the race will be unevenly worn where there had previously been a smooth, even finnish.

There are two speciality tools needed to make this repair. A race puller/installer tool for the bearing race and a press, preferably hydraulic, to remove and replace the inner primary bearing. When the primary drive is removed, it is important to replace the inner primary bearing seal, the alternator register seal or o-ring, and the starter seal or o-ring. It is also a good idea to go a few steps further. Remove the front pulley so all the left side transmission seals can be replaced. These are the main drive gear seal, mainshaft seal, shifter shaft seal, and quad seal (5 speed models). Also, the front pulley spacer should be changed on 5 speed models, as its outer circumference is a sealing surface.

Other areas that should be inspected when chasing primary drive noise or issues are the clutch hub inner splines, clutch basket (for possible cracking), clutch hub bearing, and the compensator assembly. You can find footage on all of these topics here at Fix My Hog.

Related Videos:
Chrome Inner Primary Removal Procedure
Softail Drive Belt Installation
Harley 5 Speed Transmission Project

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8 Responses to “In The Shop: Inner Primary Bearing and Race Failure”

  1. jeffery henk

    yes my question is on my 2008 road king i am having trouble removing the race on the transmission shaft on the primary side of the bike is there another way to get it off im currently redoing the six speed transmission

  2. Michael Dzurian

    I changed my bearing race and now the inner primary bearing will not fit over the new race? 2017 Wide Glide. Old bearing slips right in. Any advice?

  3. Jeff Cook

    2007 Harley Davidson road King with 48,000 miles on it 5th gear noisy compared to the rest of the gears just purchase the bike this April from a private sale bike is an awesome shape had first oil change used amsoil 2050 in all three holes bike seems to shift louder and noisy 5th gear especially when the oil gets hot when bike is cold on a cool day do not notice the noisy shifts or the fifth gear noise quite as much could this be an inner primary bearing issue or should I try a heavier oil in the transmission any help would be greatly appreciated

  4. Bruce Cory

    Bought a 2014 FXDL last October with only 900 miles, at about 4500 miles i replaced the shocks from a 12" to 13" and suddenly got noise in the primary like a whoring whine that goes away when i throttle up and comes back when i return to a steady speed or let off the gas. Its less but doesn't go away when i pull the clutch in

  5. Mark Weese

    Hi guys.... Do you have a video of the inner primary bearing replacement procedure?

  6. Harley Jared Bailey

    I had a grinding noise sometimes when I would start my 2011 Roadking Classic or sometimes shifting into 1st gear.. Only sometimes though. Well I was on my way home the other day and I was getting off the freeway and I look back and there's smoke rolling from behind me and my pant leg is coated in oil, by the time I got it home, (only a couple blocks), the engine was knocking pretty good. Did the inner primary bearing and race fail.

  7. Steve

    My 2006 harley davidson fatboy noise in primary coming from compensator side. Sounds like a high pitch whining noise. Do you have any idea what it is

  8. daniel ramirez

    need to remove the inner part of the pukkey the one that is connected to the trany.