This is sort of a resurrection of an old thread I did more than a year and a half ago. I installed the auto primary chain adjuster from Harley. Ever since I owned the bike and I was and am the second owner, the bike had a "wirring" sound. Not very loud but there. After putting the adjuster on, the same sound, no louder or quieter. Today I opened the primary to change the oil, and reached up and the top of the chain is snug. Push on it with a little force and the auto adjust drops slightly. Now I know some if not most on here think they are bad for Harleys as some say you will be replacing front bearings, but Harley has installed and mass produced hundreds of thousands of bikes with these it them. Im in the local shop every week and I have yet to see bikes in with front bearing out of them because of these. I did also check the shoe to see how wore it was. Virtually no grooves even after more than a year of riding. What is everyone take on the HD auto adjuster? Am I lucky or waiting for a bearing failure along with the several other hundred thousand bikes out there?

randy

 

The '03 bikes had manual chain tensioners, with the inspection window on the primary cover.

Not sure what auto tensioner you are talking about.....? Did you use an aftermarket tensioner....?

If you're talking about the Harley Auto Tensioner, introduced in the '07+ models years (I think I got that date correct), there is good reason for the skepticism....

The early version(s) #39929-06 were causing numerous primary belts to over tighten. That would put stress on other areas of the primary causing issues. There were many reports of collateral damage from an over tight primary chain.

I forget the year ('11ish), Harley redesigned it, part #39929-06B. Since that version has been released, there are very few issues with the HD auto tensioner...

In this pic, the older version is on the bottom and the newer version is on the top:

You can see the older version (bottom) has a "thinner" base/ramp, and the adjusting teeth are larger, covering the entire top ramp. The combination of the those two designs allowed for it to ratchet up very tight and over tighten the chain.

The newer version (top) has a thicker base/ramp and smaller teeth covering a small area of the top ramp. It looks much more robust than the older one and with the smaller teeth it would increase tension in smaller increments. This newer one has been almost trouble free, compared to the older version.

 

Hattitued, I have the top one installed. So im guessing its the newer version. Mine is a light green in colour. The "wirring" sound has always been there even with the manual although would be far louder if the primary chain was tight. I installed it according to directions and a very good youtube I found online. Cold the chain is tight on top but the ramp does move up and down when I push on it so its working. Thanks.

randy

 

Your title says 03-RKC.....I'm assuming that means a 2003 Road King Classic. I didn't know the Harley Auto Tensioners(#39929-06B) were even compatible with the earlier primaries.... Looking at exploded diagrams of the two chain case housings (a manual tensioner housing & an auto tensioner housing), I can't see how the HD auto tensioner could even be installed in an '03 primary....? Did you change the entire primary to a newer style? Are you sure you have the HD #39929-06B tensioner? How did you make it fit? I'm curious how you got the '07+ tensioner to fit in an '03 Primary... or else I totally misunderstood what you've said....

You mention your auto tensioner moves... The HD auto adjuster is supposed to automatically adjust to the proper tension spec for the chain. It' not like a Hayden Tensioner, where the chain is tight, and then the tensioner "gives" for the proper chain tension spec.

Generally speaking, a "whirring" sound is frequently a chain that is too tight. Primary chain adjustment specs from my service manuals:
From my '03 manual, for the manual chain tensioner, upward tension on a cold primary chain should be 5/8" to 7/8".
From my '16 manual, for the auto chain tensioner, upward tension on a cold primary chain should be 1/2" (.500") to 5/8" (.625").

So you should have some upward movement on the top of your primary chain, midway between the clutch and the compensator sprockets. Also, as chains wear, they get "tight spots" so you should check the chain in several different spots, and adjust it at the tightest spot.

I would suggest that your chain is too tight if I understood your explanation of its measurement. Based on the Service manuals, you should probably be at 5/8" upward play of the chain, cold, for proper adjustment....

 

Hattitude, you can't get a better show-n-tell than this.......... thanks for the write up!

 

The auto tensioner went right in with no issues. I bought it at my local dealer. They said it would fit and it did perfectly. Here is a link I also watched prior to installing. Everything went as smooth as glass and exactly how its shown on the video.
randy

 

The problem HD had was an over tightening condition and eventually causing IPB wear. I put the Hayden M6 tensioner in my 02 and 05 Dynas and never looked back. My 2013 Road Glide is a different story, gong on the problems with the HD auto-unit I changed to the Hayden for the year/model of bike. Turns out that unit was also over tightening, so bad there was a howling noise coming from the primary, so the original equip. went back. After Hayden changed the springs on their unit I put theirs back in with the newer springs, no noise to speak of now.

 

Thanks for the info....

I see by the video, they use a special auto tensioner bracket, that allows for the newer auto tensioner to bolt into the older inner primary. I didn't know that bracket existed...... The bolt holes that bracket provides are cast into the newer inner primary covers...

Good to know the auto tensioner is an option for the older bikes......

 

Hattitude, it came complete right from my local HD dealer. I took my time and even then wasn't too much more than an hour to do start to filling up with fluid. The only thing that I did and had worried about was the slight "wirring" sound I had. I know with the manual tensioner if you did it too tight it was loud, stock distances of chain deflection and it was only slight the same as I have with the new tensioner. There is some give in it to allow for tight and loose spots which is a bonus as all chains have a little of that. I think the cost was about $120 Canadain give or take.

randy

 

Problem we see with the auto tensioners is usually on bikes with built engines. People will do a hole shot or other form of hard acceleration, the chain will slacken on the bottom, tensioner ratchets up and ends up over tightening it. In these instances we install the SE manual tensioner.