I got the manual tensioner from Kreiger and will install it today. It's technically a prototype, but it will probably be the final product if no issues are present. I should know fairly quickly. While not rocket science, everything has to line up properly, of course. I'm looking forward to having a tensioner that will work no matter what.

This whole tensioner business brought up a question in my mind about the reason the KLX has 2 tensioners...mainly why? I hardly know all the different cam chain designs out there, but the ones I know only have one tensioner. Other double overhead cam engines like the KLR650, KLX450, KLX650, and many/all others have one tensioner. Why does the KLX250/300 require that secondary tensioner in the cylinder and then the spring and ratchet tensioner in the head? If anyone knows, please advise...or even just speculate.

 

We have 2?

 

Looks nice!! Interested to see your results. Ballpark $ , what does he get for these?
Dan

 

I believe $35 plus $5 postage for the finished product. He's been doing this for awhile on other bikes, and I'm pretty sure he said he even does international with some countries.

 

Looks pretty clean but I think I would rather have teh two bolts that hold it in be hex head like the oem tensioner than countersunk allen head. Seems like it would be more of a PIA to remove the rear one and more potential for buggering up the inside if the bolt seizes up a little over time. Whats the size of the allen wrench for them? Looks to be about 4mm. I know that on the compressors I work on there is more potential for damage to tool or bolt on a 5mm allen than a 6mm. I have had to do battle with stuck and stripped bolts and avoid it whenever possible. (Thats why I got rid of the allen bolts in the Nomad rack.
Cheers Jim

 

I am a member here and I can fill you in a bit on the tensioners. I am definitely anxiously anticipating feedback from TNC. We spent a fair amount of time on getting this right. Two were hand cut then I found the plungers were located in the wrong position. So on the remake I actually got them cut in my normal production process. It is essentially exactly what will be made if all works as expected.

The bolts are countersunk for a few reasons.

One is to keep the lock nut totally open for a wrench.

Two is that I do not like the "pre-rounded" Kawasaki bolts and with the way the tensioner fits the head, angled downward, I don't anticipate too much issue with the zinc coated fasteners. But that can be dealt with.

Three - aesthetically they just look professional.

The kit is made the way I wanted one, back when I started making them for the KLX650 and Zephyr 550/750 when no one would list or make them. It has everything needed for the conversion without a visit to a dealer.

I've run a manual tensioner for over 28,000 miles in the KLX650, having made 4 adjustments (less than one full turn of the bolt, in total less than 1/16" movement) in that time, and now about 8000 miles in the Zephyr with no adjustment yet. I only removed the original manual conversion in my KLX to run my first 650 tensioner before I sold the second one, otherwise it would not have been taken out. The Zephyr ran the first one of those I made, before one was sent out too. Oh, it should be mentioned I had to do a top end to put in new chains (2 in the KLX) because I believed it when people on the forums said they were all noisy and it was normal. I put in a new OEM "automatic" tensioner at 5000 and rebuilt after the second "automatic" tensioner failed by 15,000 miles. When the same was said about the Zephyr, I knew I wasn't buying that. Now both the Concours and Eliminator groups, where the same is said and it apparently is common practice to have to pull supposedly "automatic" tensioners for cleaning and resetting, are discovering the same tensioner that fit the KLX650 fits their bikes and are in touch.

If the tensioner does the job as expected for TNC it will become available.

I've shipped to 15 countries including of course the U.S. and Canada by U.S.P.S. flat rate Priority. A few of the more interesting were Latvia for a KLX650, Poland for a Zephyr, and Malaysia for a KLX650.

A special order without the countersink fasteners can be done if someone requests it. I don't carry any bolts like the stock ones, so the fasteners wouldn't be included in that case. I just have a liking to the clean look and accessability.

Because Kawasaki used an O-ring instead of a gasket, special gaskets were laser cut and two extra will be sent with the tensioner in addition to the one on it.

If it works as expected, I can be PM'd or emailed from here for more details.

By the way, the KLX650 uses two tensioners in similar fashion to the KLX250, but the spring loaded one is on the lower chain. I looked at the parts diagrams for the 2007 - 2010 250 and it appears they are using one as a sort of "shock absorber" with minimal effect and the other for the actual regular cam chain tension to take out the large amount of the slack. There is one thing to realize about the function of the tensioner - it is to take up the slack, not actually to put tension on the chain. Perfect "tension" is zero tension. The springs in tensioners are only to push the plunger forward, not to keep it forward. That is the job of the ratchet. Too much spring pressure will cause wear on the sliders and cam drive, otherwise they could just put on "mega springs". Again, ideally everything is barely skimming over each other in an oil bath, with the occasional hit from deceleration when the crank slows quicklly and the momentum of the cam drive has to be slowed.

The problem is when the ratchet mechanism, which requires incremental movement to lock in properly, fails to lock in under the progressive wear/seating of the cam drive. If it doesn't seat completely it can be kicked back resulting in damaged ratchet tooth and pawl edges, which will appear polished if viewed under a magnifier. The slipping back and forth will have the metal polishing the surfaces over which they slip time and time again. One Concours owner mentioned this and I saw it on my second tensioner in the KLX. It doesn't happen on all tensioners due to tolerance stacking and the minimal movement due to wear/seating which will have some tensioners work fine and others fail.

By the way, I just noticed - it's actually spelled Krieger. Very German. A common mistake or even keying error, as I have done that before, catching the e before the i.

 

Interesting. I might be in the market for one of those bad boys.

 

Are there really two tensioners, or actually one tensioner and a guide? Looking at the parts breakdown, I only see one spring actuated tensioner.

 

There are two tensioners. The lower one in the cylinder pushes on the very tall, single guide block at the rear of the motor. This tensioner has no locking ratchet...just maintains a spring pressure on the guide block. The service manual refers to it as a "chain tension spring".

The ratchet tensioner is just above the chain tension spring, and it's located in the head...pushing the same tall guide block.

I had not noticed that the KLX650 had two tensioners also. The KLR650 just has one. I'm speculating that it's because of the higher rpm of the KLX series...perhaps? But...other more modern double overhead cam 4-strokes only have one...like the KLX450. Maybe an older overkill idea from Kawasaki?

On the KLX250/300 manual tensioner, I'm in touch with Mark Kreiger about shortening the exterior portion of the threaded plunger. It's a little too long as delivered on this prototype, but if he gives the OK, I'll cut it down. My Muzzy head pipe is fat and interferes with the adjusting acorn nut.

 

Ahhhh, the headaches of a prototype...

Changes are afoot.

I only wish I could be working along with TNC to get the resolution quicker. It's tough to not be able to be directly involved with the installation/adjustment portion, but we do what we can.



In a side note, the reason for the two cam drive chains on the KLX650 was they did the 2:1 drive reduction at the idler gear set midway between the crank and head to enable the cam sprockets in the head to be significantly smaller. The tallest part inside the top of the head are the cam drive gears, so making them smaller can reduce the overall height. With a 650 single shorter is better., this is one big engine.