All is running well since rebuilding the bike with the new 96″ S&S motor. I really like having the added punch on the top-end.

After a few good trips and a few thousand miles I started to notice a bit of a noise. Sounded like a chain slap in the primary. I took the bike up to John at the Fix It Center and had him give it a listen. He said it sounded like my primary chain may be out of adjustment and suggested I install a Hayden M6 Automatic Chain Tensioner. He had one, it was about 90 bucks so I figured I would give it a try.

Installing the Hayden M6 was pretty simple. Just drain the primary oil, remove the outer primary, remove the stock tensioner, and install the new M6. Once the M6 is installed you simply add shims until you get to the correct tension.

Hayden M6 Primary Chain Tensioner Installed on a 1992 Heritage Softail

The instructions stated that if you had to add more than 5 of the supplied shims then it was probably time for a new primary chain. Wouldn’t you figure – it took five of the thick shims to get my chain to the proper adjustment. Back up to John’s for a new chain.

John had a chain in stock, and I picked up up the primary gasket that I had forgotten to get earlier, and a couple of quarts of Harley primary oil. I also had to borrow an impact wrench.

View of the Shims, Shoe, and Spring on a Hayden M6

Installing the primary chain was also pretty simple. Just remove the clutch hub nut (left hand thread – backwards as I like to call it) and the nut that holds the sproket on. Remove the clutch basket and sproket, install the new chain, put the clutch basket and sproket back, make sure the chain is aligned correctly, add a little lock tight and put the nuts back on (make sure to check your service manual for the proper torque).

Worn-out Stock Harley Davidson Primary Chain Tensioner

As you can see from the above picture the shoe on the stock chain tensioner was pretty worn out. After installing the new primary chain the M6 did not need any shims but I put in one of the smallest ones just cause I felt better having one there, instead of the spring just resting on the inner primary cover.

After a quick adjustment of the clutch I reassembled the outer primary, added the primary oil and took her out for a test. It took me about and hour and a half of actual work to install the chain tensioner and the new chain.

So far after a few hundred miles the Hayden M6 Chain Tensioner seems like a good investment. The first thing I noticed was a considerabl decrease in vibration at high speeds and it is also a lot easier to find neutral at a stop light.

If you’ve got a hundred bucks, a couple of hours, and you are still running the stock chain tensioner on your bike, I think the Hayden M6 is an excellent investment to make the next time you service your scoot.

The Hayden M6 Primary Chain Tensioner is available at J & P Cycles.
Search for part number 601-051 (Big Twin 1965-2000), 601-006 (Twin Cam 2001-06), 601-168 (Sportster 1991-2003).