December 06, 2019, 06:05:27 AM
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Author Topic: Manual Primary chain tensioner?  (Read 656 times)

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October 26, 2019, 03:39:47 AM
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jordan1200


I wanted to ask what other think of going to a manual primary chain tensioner over the automatic on on my twin cam. I have read many online posts of the OEM units over tightening the primary chain and causing wear on things like bearings and shafts.

Is there any truth to this?

Are the manual ones a good alternative? If so SE, Baker, twin power?

Are they really as loud as I have read, or are they just being installed to tight?


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October 26, 2019, 08:08:53 AM
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HDBitchin

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Here is a link to a discussion on the forum about auto chain tensioners and manual tensioners. This link below jumps you straight to Reply #8 in a thread that has a larger discussion on other primary issues.

Manual Primary Chain Tensioner versus Auto

The auto tensioners have been claimed by the makers of the manual tensioners (Baker Attitude Adjuster or a Hayden M6 or Twin Power) to cause premature mechanical failures and unnecessary stress to engine, transmission and primary bearings. Is that a marketing claim?

I have owned Harley-Davidson motorcycles with both. My 1995 Heritage has a factory standard manual adjuster and I have owned various newer Twin Cam HDs that had the auto tensioners. Never had an issue.


October 26, 2019, 09:03:53 AM
Reply #2
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jordan1200


Thanks

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October 26, 2019, 09:34:16 AM
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NoSuperSlabs

Supporting Member
Not sure if it is true but I have heard that aggressive riding habits could ratchet the auto tensioner design into a very high (tight) position. Then that could put extra force on bearings and shafts. 
Two Lane Highway


October 26, 2019, 09:38:13 AM
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maniacmac

Global Moderator
Anyone who has ridden with me knows I will ride very hard at times ( Tank can verify  ) and my tensioner as never over tighten my primary chain as per my 10,000 mile inspections, and I have 44000 miles on my S.G. I believe Tank made a very good point stating maybe it's a marketing ploy IMO
CARS SUCK!

October 26, 2019, 09:44:52 AM
Reply #5
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HDBitchin

Administrator
Anyone who has ridden with me knows I will ride very hard at times ( Tank can verify  ) and my tensioner as never over tighten my primary chain as per my 10,000 mile inspections, and I have 44000 miles on my S.G. I believe Tank made a very good point stating maybe it's a marketing ploy IMO
I can verify. He rides very hard at times!!

October 26, 2019, 11:04:12 AM
Reply #6
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jordan1200


I have read(can't remember where that early versions of the automatic primary chain tensioner had larger teeth and thus would cause over tightening.
No idea what year and era or if it's true

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October 26, 2019, 12:38:04 PM
Reply #7
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HDBitchin

Administrator
I have read(can't remember where that early versions of the automatic primary chain tensioner had larger teeth and thus would cause over tightening.
No idea what year and era or if it's true

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Something was changed on that part over the years so you might be right. HD introduced the primary chain tensioner in 2006 as P/N 39929-06 and it looks like they have changed it twice (releasing an A and B version) over the model years so you could be correct about the teeth. The current P/N is 39929-06B and it is used all the way up to model year 2016 (in the 2017 model year the Milwaukee 8 came out and things in the primary changed). As for what years during the 2006 to 2016 model years that use that P/N they introduced the A and B changes and what were the changes? I don't know.



October 26, 2019, 12:48:32 PM
Reply #8
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jordan1200


I wonder if there is any way to tell her you have?

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October 31, 2019, 07:29:14 AM
Reply #9
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bigj59


I went with a Hayden M6 Auto chain adjuster on my 2010 road king love it

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November 05, 2019, 02:41:43 PM
Reply #10
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Screamin beagle

Supporting Member
You can pull it out and look at the part number lol...actually you see the difference between the two. The older one has courser teeth and the bridge is thinner,  the newer version has finer teeth and a thicker bridge. The new one was supposed to alleviate the over tightening. I had the older version and I ended up needing a mainshaft gear bearing two summers,ago. Was it caused by that tensioner? Couldn't tell you either way. I put a Hayden in at the time I rebuilt the transmission and it certainly minimizes that " they all do that" first gear clunk. Got about 15k on the Hayden and it has very little,wear so far. Some people say the manual ones are noisey,  can't comment on that. I'd say check your chain tension once a year and if it is in spec then save your money for gas and beer...or chicken wings.
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November 05, 2019, 02:46:13 PM
Reply #11
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jordan1200


Good advise and thanks for the details on the difference between the two tensioners

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November 05, 2019, 08:40:58 PM
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bc45

Global Moderator
I went with a Hayden M6 Auto chain adjuster on my 2010 road king love it

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@bigj59  just curious what do you like about the Hayden over the stock adjuster? less noise, smoother going into gear? 

November 07, 2019, 05:42:46 PM
Reply #13
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jordan1200


Anybody know anything about these primary chain tensioners

So hot bikes HB125-07



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November 08, 2019, 03:59:44 PM
Reply #14
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HDBitchin

Administrator
Unfortunately I can’t comment on the Hot Bike HB125-07 as I have never even heard of their product.

Just to add some more confusion here is a DIY guy’s video that is installing the Hayden tensioner. The first part of the video has an interesting but confusing part where he tries to explain the 3 versions of the HD auto tensioners and even though he gets his facts messed up about what the versions were called it is worth watching as he concurs with your earlier post where you said the teeth were different sizes with the original and the A and B versions. He says they have a C version and I don’t believe that to be true. From the parts manual I looked at there would be the original and an A and B but no C.

I am just posting his video for the discussion about the 3 versions of the HD auto tensioner. The rest of what he says in the video about the Hayden and how he ended up using just one spring, I don’t endorse it. In fact I would say he should do as Hayden suggests in their install. I wouldn’t second guess Hayden as he does.


 



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