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Welcome to Krieger Cam Chain Tensioners! I did not intend to make this product. It came out of necessity. Both of my two Kawasaki motorcycles, a KLX650C and a Zephyr 550, had “automatic” cam chain tensioner failures. The KLX had TWO tensioners fail, one at 5000 miles and the other at about 13,000 miles. After the second tensioner failed the cam chains had to be replaced. I had the top end rebuilt at the shop where I sold bikes part time, I was a quality engineer at that time. I had the skill to do the work, but it was easier to sell bikes to pay for it to be done by the mechanics, who are friends too. I looked at the second failed tensioner using a magnifier. It
was clear what the problem was. The way the adjuster works is as the chains wear
the tensioner will have a light spring push in against a plunger with a toothed
rack stem. A pawl is supposed to lock the rack when it moves in. The problem is
when the plunger moves in very small amounts the pawl may just barely slide over
the top of the tooth and any back pressure from the cam chain drive will snap it
back over top the tooth. That will round off the edge of the tooth and pawl,
eventually allowing the plunger to push back and forth over 3-4 teeth of the
plunger. I could see the damage by the polished tooth tops and the magnifier
allowed me to see the edges were rounded. This tensioner movement back and forth
will allow chain whip and snatch in the engine. That will cause valve timing
issues in starting and running and will wear out the cam chain (chains in the
case of the 650, it uses two chains). The key point is the cam chain should only have the slack taken out, not actually have much tension on it. Perfect adjustment would be zero pressure/no play. Still a little loose or a little tight based on variability in adjusting a manual tensioner is relatively insignificant when compared to the stock “automatic” tensioner what will allow ¼ to ½ inch movement of the plunger. The fixed bolt will not back off at all. Some people will try to use the stock tensioner in a manual method by backing out bolts until the pawl snaps into a tooth then tighten up the bolts. This is significant tension and will wear both the tensioner shoe in the engine and the cam chains. I even had one KLX owner who thought it was no big deal to replace cam chains every 12,000 miles! All to avoid buying a manual tensioner. Back to the story… the KLX is alive and doing fine after over 27,000 miles with the modified stock unit and now my own tensioner. I bought a Kawasaki 550 Zephyr, I like that old school superbike look. I rode it a bit and the top end is buzzing like a hornet’s nest, rarely quieting down when the tensioner tries to work. I have a pretty good idea what is wrong, but I still asked on some forums. The biggest response I got was “It’s normal.” Or “It’s primary drive chain noise.” I eliminated the latter possibility by doing the simple test of putting the primary chain under tension, which eliminates the sort of light slapping noise. I put the bike in gear, held the brake, and lightly eased out the clutch power-braking the bike slightly. Most all primary noise will go away. My “hornet’s nest” didn’t. One or two mentioned the tensioner and Kawasaki had some history of tensioner failure on sportbikes, and, as I am learning, some others too. So, out comes the tensioner, it is definitely not functional. It is also not able to be converted to a manual unit as the KLX had. Kawasaki’s replacement was essentially the same tensioner that went bad TWICE in my KLX. No way that’s going in my bike. I figured I’d pay the $50+ for an aftermarket manual tensioner, but wonder of wonders, my bike is not listed and a call to the supplier verified they didn’t list or make one specifically for it and had no clue what might work. I measured up the length needed to reach the cam tensioner shoe and emailed the information to the manufacturer to see if the manufacturer’s GPz550 tensioner would work, the body was the same but was the bolt reach? I also asked if it didn’t could they make one with a longer bolt? I got no response from the company. So, with a bit of inspiration from a fellow Zephyr owner, I made my own – and four extra for both the Zephyr and KLX. I bolted in one of the Zephyr tensioners and did an initial adjustment, snugging up the bolt by hand while turning over the engine with a ratchet to get the slack on the tensioner side, backed it off about 1/8 turn to allow for thermal expansion, and when the bike fired up – NO MORE HORNET’S NEST BUZZ! Talk about happy. And a few thousand miles later still no noise… Yeah, “It’s normal.”… my foot! The KLX tensioners sold almost immediately, the Zephyr tensioners catching on slowly. To date I’ve sold over 30 tensioners, with one Zephyr owner posting a comment in the Zephyr-Zone about his bike being quiet for the first time ever. I have customers in Texas, California, New York, Wisconsin, Minnesota, Ohio, and some other states I don’t remember right now, not to mention one sold to a WERA vintage middleweight/heavyweight superbike racer. I also sell overseas, having tensioners sold in Maylasia, the UK, Finland, and soon Australia. I use the parts I make. I took the converted tensioner off my KLX and put on one I made before I sold the first one for a KLX. I also rode my Zephyr with the tensioner in it before I sold the first one of them too. Unfortunately I can’t do that with every model, but I know they work as intended. I also made the kit as I would like to have if I bought it
from someone. I figure the flush head fasteners open up the lock nut so a wrench
will fit and turn, plus it looks good. I made an O-ring seal so it won’t seep
oil like the conversion did on the KLX. I used 6061T aluminum because of
machinability and corrosion resistance. I include the OEM gasket from Kawasaki
(and other manufacturers on those tensioners) because you will possibly need it.
I include the 4mm ball end allen wrench for the flush fasteners because, I don’t
know about you, but I can never find the right allen wrench I need when I need
it. Finally I include the directions for installation and initial adjustment
developed as I installed them on my bikes… wrote the notes as I did the work. As I said, I didn’t intend to be doing this, but I am and it’s
fun. I hope I can help you out with a reasonably priced part to help keep your
bike running great. |
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Copyright © 2009
Krieger Cam Chain Tensioners
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