Does anyone know if there was a change in design on the H-D automatic primary chain tensioner? The part number now is 40063-05A, and I believe that the A means design change. I don't have this tensioner but am thinking of adding one this winter. Any help is appreciated. Thanks.

 

That's a 05 part#. The new auto tensioner isn't a good idea because it would most likely have your chain running too tight. I plan to get rid of mine for just that reason.

 

So I assume it is back to stock for you? Or do you plan to try the M6 or H-B 125?

 

How does the H-D automatic tensioner only ratchet in one direction, supposedly leading to overtight chains? Thanks.

 

It has a ramp thats spring loaded and teeth that engage as it goes up. It's a one way deal as it won't come back, but it may chatterwithin the area of theteeth between it's engaged area and the next tighter spot when close to it's next tighter position. Problem occurs when it takes up the slack when coldif it is capable of doing so. If it does this in a slacker part of the rotation instead of the tightest spot as is done with manual adjusters it will tend to be too tight for normal running when the bikes primary is hot. Another case would be if it's not in position under normal conditions to self adjust, but very close to it, a high load imposed on the primary chain will stretch it enough to allow it to ratchet into a tight conditon. Starting the bike on a really cold morning could if it's close for the next notch when it was hot outside to make it too tight on the next hot day. I personally don't think it was well thought out for good function, and will replace it with a better engineered component.
Ron

 

rbabos,

This device doesn't look like one I want in my bike's primary. For the time being, stock is fine. Thanks for your comments, but I'll leave well enough alone.

Paul

 

Unless you know of an aftermarket tensioner that will fit into the 07 primary, replacing the auto tensioner will involve replacing the primary housing as well. The 07 case is redesigned and as a result older style tensioners will not fit. The retro fit automatic tensioner from HD has an included brecket to adapt it into the older case.
This webpage shows the new tensioner being installed in a pre 07 primary.

http://www.hotrodsbikeworks.com/tech.../photo_16.html


07 FXSTC

 

Thanks for the article.....I knew it wasn't a bolt on, but there is room inside the new cover to weld a mount for using the previous tensioner. You could also modify the new auto tensionerfor manual operation and adjust through the bottom of the cover ala Sportster.

 

I put one in my 05 classic,It howled so bad I took it out after 1,000 miles. My 07 has it and it's quiet?