I have heard that the primary chain tensioner can ratchet up too tight. Is this something that readjust it's self after the bike cools down? It seems this would put a lot of stress on the chain and bearings. Is this a bad design or nothing to worry about?
Once the OEM ratchet type tensioner tightens, it stays tight. It does not release the tension on the primary chain.
Replace it with a Baker Armored Attitude Adjuster: https://bakerdrivetrain.com/products...nt=39606989774
I suspected this may have been occurring with my 2010 Twin Cam B engine on my FatBoyLo. So opened it up this winter and sure enough. Tighter than I felt it should be. Ended up ordering the Twin Power tensioner and set my horizontal chain slack right in the middle of 5/8 to 7/8 inch spec. Supposed to recheck every 5000 miles thereabouts. And the factory chain tensioners do not slack once they spring climb up the serrated ramp.
When I bought my bike the dealer warned me about this. Said they feel it was a result of aggressive downshifting causing slap in the primary. They were seeing some premature bearing failures caused by too much tension on the chain.
I had the over tight problem on my '07 RK when I bought it. Bike had 40k miles on it. A 103 kit had been installed at 18k. Stock tensioner was broken.
Broken stock tensioner.
M6 still working great after 6 years.
Chain was so stretched it had to be replaced. Bearing was also replaced. I went with the M6 spring loaded tensioner. Seems like the hopped up bikes have more problems with the tensioner than stock 96ers. Riders roll on the throttle hard then roll off fast.
I have heard that the primary chain tensioner can ratchet up too tight. Is this something that readjust it's self after the bike cools down? It seems this would put a lot of stress on the chain and bearings. Is this a bad design or nothing to worry about?
Depends on the year bike...
I believe it was 2007 when they went to the auto adjusting primary chain tensioner, #39929-06A. There were numerous reported problems about it ratcheting up too tight and then causing other issues because of the tightness... once it tightens up, it will not loosen on it's own. It's got a ramp with steps that act as a ratchet effect- one way only....
I believe sometime in 2010, HD started using an improved version of the auto adjusting tensioner, #39929-06B. On one of the forums, someone posted a pic of the two tensioners side-by-side. The newer version was certainly more robust, and not as prone to over tightening. There have been far fewer complaints on the newer style auto tensioner.
Some are of the opinion and that certain driving habits, like heavy downshifting/engine braking on an engine that's not at operating temperature, greatly contribute to the over tightening.
Hayden & Baker both make a good replacement tensioner. The Hayden has spring tension and the Baker manual adjusted tension. The Hayden did have issues in the 103ci bikes. The springs were too strong and caused some problems. They eventually changed out the springs to a lighter tension... I had a Hayden, but didn't install it in my '12 Limited. Partly because I lost faith in it's quality over the spring debacle, and partly because I found out I had the newer auto tensioner. I put my Hayden on the shelf, it's still there...
I had 40K miles on the '12 Limited and now have a '16 Classic, both 103ci with the newer auto tensioner, and I've not had an issue....
I believe it was 2007 when they went to the auto adjusting primary chain tensioner, #39929-06A. There were numerous reported problems about it ratcheting up too tight and then causing other issues because of the tightness... once it tightens up, it will not loosen on it's own. It's got a ramp with steps that act as a ratchet effect- one way only....
I believe sometime in 2010, HD started using an improved version of the auto adjusting tensioner, #39929-06B. On one of the forums, someone posted a pic of the two tensioners side-by-side. The newer version was certainly more robust, and not as prone to over tightening. There have been far fewer complaints on the newer style auto tensioner.
Some are of the opinion and that certain driving habits, like heavy downshifting/engine braking on an engine that's not at operating temperature, greatly contribute to the over tightening.
Hayden & Baker both make a good replacement tensioner. The Hayden has spring tension and the Baker manual adjusted tension. The Hayden did have issues in the 103ci bikes. The springs were too strong and caused some problems. They eventually changed out the springs to a lighter tension... I had a Hayden, but didn't install it in my '12 Limited. Partly because I lost faith in it's quality over the spring debacle, and partly because I found out I had the newer auto tensioner. I put my Hayden on the shelf, it's still there...
I had 40K miles on the '12 Limited and now have a '16 Classic, both 103ci with the newer auto tensioner, and I've not had an issue....
If this design causes as much problems as people are saying, don't you think this mod should be a "sticky?" (BTW, Do you remember exactly what shelf you put your Hayden on? Is this the one that would give a Night Train problems? Want to sell it? haha only if it would perform as new... )
If this design causes as much problems as people are saying, don't you think this mod should be a "sticky?" (BTW, Do you remember exactly what shelf you put your Hayden on? Is this the one that would give a Night Train problems? Want to sell it? haha only if it would perform as new... )
Not sure which problem you're talking about.... the over tightening with HD #39929-06A or the issues with the Hayden M6 on '09+ 103ci touring engines....
Both have been discussed on this forum and could be found with a search.
As for the M6 Hayden, here is a pic. The springs on the left were originally sent with the Hayden. The directions called for (IIRC) 1/4" minimum gap at the base, but most could only get 1/8". Hayden said it was fine, but many reports of tight primary chains, and then Hayden switched the M6 to the shorter spring stack (on the right).
It must be said, Hayden was responsive to the issue... they sent me replacement springs for my M6 free of charge. Apparently, they just didn't test the M6 in the newer 103ci touring bikes to see their install directions were off and it was too tight.
I also have to say, other than the M6 in '09+ 103ci touring bikes, I've never heard of anyone complaining about a Hayden tensioner. All other applications they apparently work very well....
The HD automatic tensioner is junk. Mine started being difficult to shift and made an unusual sound shifting into first. When I took off the cover the primary chain was tighter than a banjo string. Replaced with the old style adjuster and check it when changing the primary. Not a big deal to check and adjust if necessary.
05-10-2018 | 01:07 PM
Primary chain tensioner ratchets up too tight?
