M6 Primary Chain Tensioners for XL's


We're often asked about these spring-loaded primary chain tensioners that are available for XL models, and whether they're a worthwhile investment. I've used these devices and this is to share my experience.


I personally fitted four different Buell tube frame models with spring loaded tensioners from Hayden, dubbed the "M6". The first sign that something wasn't right came about 1000 miles later on the bike that was getting ridden the most of the four. I noticed an unusual amount of noise in the primary.


I pulled the primary cover and found this:



That's exactly how it looked when I pulled it out of the motor, stuck down. I forced the shoe out and this is what I saw:



As you can see, the primary chain was grinding a burr into the tensioner frame. The shoe was hanging up on that burr rather than freely sliding up. Large quantities of steel filings were being deposited into my primary and transmission and a more serious failure was imminent.


It was installed exactly correctly, it's not rocket science to put one of these things in. And there's really not a lot of room for error on the installation anyway, although I suppose a person could get the thing reversed in there. But I had done it properly.


I pulled the other 3 tensioners out of their respective motors, and although they weren't stuck like this one, every one of them had evidence of the chain grinding on the frame. Not good.


Speaking of tensioners, if your XL or Buell was made prior to early 2001, there's a good chance it has a light duty tensioner installed. See the one on the left below:



Note how much thinner the steel plate is on the left tensioner than on the right tensioner. These light duty tensioners are subject to failure, particularly in high horsepower applications. The steel support plate literally breaks in two. Always update your tensioner to the new style on the right. NRHS normally stocks the heavy duty tensioner just because we see this so often and we update every motor we come across. Give us a call if you're in need of one, it's not an expensive piece (under $25) and it can sure prevent an awfully expensive failure.



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