red, when it functions consistently that would be correct. You may have a fully functional tensioner...and frankly most probably do. However, many do not. Oddly it's not one of those absolute "smoking gun" deals as to exactly what fails...and it may not be the same issue every time. Some have noticed the teeth in the ratchet have been jumping back and forth. Some find the ratchet doesn't move forward in a timely manner. And there may be more issues on others. A manual tensioner is absolutely bomb-proof if you take the time to adjust it every once in awhile.

 

read the post again,, he said ONLY with a load on it not in neutral.

 

Tell that to the two of them I had go bad in my KLX... and the cam chains that were ruined...

Not to mention the one in my Zephyr that I got out before it ruined the chains there. Not all tensioners are up to the task.

 

You're right, I'm wrong. My error.

 

I'm not quite sure why people say manualy adjusting the tensioner will prematurely wear the cam chain??

technically, the plunger should automatically "click" and put tension on the cam chain to stop the rattling....it's designed to put tension on the chain. If it doesn't, all that is being suggested is "helping" the autotensioner along to the correct position it should be at in the first place...

after all, of the 2 or 3 people that actually pulled the tensioner out have stated that it's usually not even at the half way point

now.. if you mess up... I'd imagine that's a different story...

am i missing something? can someone school me?

 

You asked for it:

"Now to address what I observed before making my first manual tensioner. The rack and pawl design with a spring will constantly put some minimal pressure on the chain slider which would promote wear. The spring isn’t strong enough to resist kickback in the chain under crank deceleration, so it isn’t of any value in tension control in that area. What it does is put enough pressure on the rack to push it forward and the pawl clicks in as the chain seats in and cam drive wear occurs… but not always completely.

The thing I've found interesting in both the KLX and some other forums is the expectation that Kawasaki engineers are infallable and that replacing these tensioner parts and resetting supposedly automatic tensioners would be a normal practice. If it is automatic shouldn't it be automatic? Why should I "reset" or back out until I hear a click, effectively doing a manual tensioning and also making it too tight? I don't buy it. One guy on the KLX site thinks it's okay to replace HyVo chains at 12,000 miles. Those chains are the same design used in some automobiles that run for about a lifetime and on the primary drives of many in-line fours. Other guys think it's okay to back out the mount bolts to effectively override the automatic system.

Now to address what I observed before making my first manual tensioner. The rack and pawl design with a spring will constantly put some minimal pressure on the chain slider which would promote wear. The spring isn't strong enough to resist kickback in the chain under crank deceleration, so it isn't of any value in tension control in that area. What it does is put enough pressure on the rack to push it forward and the pawl clicks in as the chain seats in and cam drive wear occurs… but not always completely.

The key point is that the automatic tensioner clicks in incremental amounts. Cam chains wear/seat dynamically (no increments). When the wear, which by my manual tensioner adjustments has proven to be minimal, isn't enough to move the rack forward forward enough to seat in, but just barely over the tip of the tooth there will be problems. And of course there is no way to tell this. Under cam drive deceleration the rack can kick back hard enough to force the rack back over the pawl, damaging the edges of both by chipping off the edge. This is the same effect as the rounding of shifter dogs when gear boxes are abused with incomplete or missed shifts, but on a much much smaller scale. It takes a magnifier to see the wear (actual rounding), but not the evidence of the wear (polishing of teeth). If this occurs over and over the edges round, much like shifter dogs can, but eventually the rack may start skipping over multiple teeth.

After two of the OEM tensioners in 15,000 miles, the second one costing $70 initially and then about $300 in rebuild costs after it failed, I have no qualms about recommending a manual unit. With simple adjustments on fairly wide intervals after seating in of any new components, the unit is reliable as a rock. I've got 28,000 on my bike with a manual unit, I can't remember now when the last adjustment was made, but it still isn't making any rattling noise except when cold and that is due to play allowed for thermal expansion. I have another rider with a Concours who has 23,000 on his with the same minimal adjustment. Less than one full turn of the adjuster bolt. It is so small a movement if you look at the OEM rack you'll understand why it is possible to have one go bad and another one go without issue. It's just not worth the $70 for the automatic one if it fails again. The manual units are more reliable, the biggest problem with them is when a rider doesn't recognize when it rattles it is time to adjust it.

Now if you adjust the manual tensioner the way I describe it, or another way I learned from the Eliminator owners, you will have taken virtually all the play out of the cam chain drive, but put virtually no tension on it. The OEM automatic tensioner's spring actually does put unneeded tension on the drive all the time, pushing in. All that need be done is take out all the slack, that is ideal.

The play is taken out by either listening for the rattle caused by the loose chain play, which can also be felt if actually doing the turning in by hand. I will tell you I put a socket on my inch/pound torque wrench, held it and twisted as hard as I could... I couldn't even get the beam to deflect. So obviously hand tightening is nearly impossible to overtighten, but I still go by the sound and feel.

Since this is all done at full operating temperature everything is thermally expanded to probably a thousandth or two of maximum growth over all, all inclusive. In other words the drive is as tight as it will get due to expansion. This will result in a very tiny amount of slack when the engine is cold, but that slack is so little it will be inconsequencial as my 28,000 miles show it to be.

As for the chain, again those chains are the same design used in some automobiles that run for about a lifetime and on the primary drives of many in-line fours. They are known for durability when bathed in oil - which they are. Do the research on the internet, I did. I also have never seen a cam chain actually break in the 22 years I spent in a mid-size dealership where I used to love to go hang out in the shop. The one thing I have seen is damage caused by loose cam chains beating up the sliders, variable cam timing as the chain slack allows it to vary by a large amount when the tensioner allows .250 movement when the rack pushes back and forth over 3-4 teeth, and overly worn cam chains from that slapping and snapping around. I will say I did see some Honda ATC200 engines, which use a roller chain, that didn't have the manual adjustment done on them at all, resulting in a lot of chain slap... enough to break the tensioner sliders in them and actually cut through the cylinder cam drive tower area on one. Incredible!

Now the negative on the manual unit. You have to be aware of any ticking coming from the left side cam drive area when it's hot, so you can k ow when to adjust it. That's an actual audible signal that is far quieter than the clatter from a failed OEM automatic tensioner, indicating far less play. It's usually a small adjustment of 1/8-1/4 turn of the adjuster bolt (one full turn is .060" on the M8-1.25 bolt I use) and might only come about every several thousand miles.

You'll actually check your valves more often than it will need adjustment. All you do is every so often at the end of your ride let the bike sit there and run while you take off your helmet and listen on the left side to see if it's ticking at all. Just don't confuse valve tick from the head with chain ticking from the tensioner area. I even got a mechanic's stethoscope to do mine just to be sure. It was more for the Zephyr where the drive is in the center of the engine, the outside cam drives are easy to hear."

This sums up what I've learned over the past ten years from both observation, reading, and my mechanical engineering background. I hope that helps.

 

I think what Mark, klx678, is getting at is the fact that too much tension can indeed damage the guide blocks and/or the chain over a much shorter period by over tensioning the chain. Learjet's method of unbolting the tensioner probably has the most potential of damage and wear if not done very precisely and exactly. I'm sure he's capable of assessing how much extra tension he's feeding into the tensioner based on reading his past posts and his rebuild of his cam chain components. But you can see how someone with less mechanical experience could allow this method to introduce way too much tension.

Even the method of inserting an allen wrench or other long, skinny tool into the spring bore of the OEM tensioner to make it "click", could have some drawback. I've used that method myself, but how much force is any given person actually applying by pushing in on the plunger by hand?...not enough?...too much?...just right? You can see the variables. Addtionally, if you don't load the front half of the cam chain by rotating the engine from the flywheel bolt, I don't think you're accomplishing much. You won't get the slack out of the front half of the chain by just pushing in the plunger manually.

 

Awesome! thanks for the explanation TNC. man, i hope i did mine right :S i guess only time will tell.

 

Post nuked.

 

Thanks folks. I just bought a slightly used 09 KLX250sf. I will be picking it up tomorrow. I will also be watching for cam chain noise.

David