CCT Cam Chain Tensioners explained

Essentially the most common design used today consists of a spring driven worm mechanism and sector type set up. Normally is composed of a housing that bolts to the cylinder in such a way as to bring the plunger of the tensioner to bear on a swinging tensioner shoe, as in the picture below. The plunger itself has an internal screw gear cut into it, and is keyed to the housing so that it cannot rotate along its length. A torsion coil spring is anchored to the housing and drives a shaft cut with a worm gear the threads into the plunger. This is the part that you turn to release tension when servicing.

When slack appears in the chain, the spring is able to rotate the internal shaft steplessly until the slack is gone, but if the chain tries to push back on the plunger, it cannot do so any more than you can pull a bolt out of a threaded hole without turning it; worm gears can't be back driven. Simple.



Other designs include simple spring loaded arms or plungers, often with ratchets to prevent pushback, some driven by hydraulic pressure from the engine oil pump, etc. That is the case of my Yamaha Tracer CCT, Look at the picture below. A down side of these spring loaded arm CCT's actuated by oil, is that they are designed to work with a certain oil pressure, so if by choice you change the oil of your motorcycle keep this in mind, as it can lead to premature failure.

So you read this article, and you thought, ok so how do I know my CCT failed? well most likely you will start noticing a tick from the side/back of your engine (normally where CCT are installed) and in more extreme cases the rattling will be too much, because the chain will have more slack than necessary and will make the chain guides hit the side of the block (if too much chain guides can brake, no one wants that! ), this guide hitting the block will be making all kinds of "interesting" noises. Do not panic though, only reason to panic is in case you chain skips a tooth, if it does, believe me! you will notice immediately causing sweats / panic and a immediate loss of capital.

So your motorbike has a tick or sounds like an old school Ducati, even though you don't have a dry clutch ?

Below is a small DIY that I took from FZ09.org Forum:

First thing to do is to unwrap your APE CCT and make sure the adjuster goes in and out freely (4mm allen). Then unwind the adjuster all the way to allow it to go in the engine and clear the frame.

1. Remove the LH side engine case cap using a 14mm allen socket (same as front wheel) and remove the 6mm bolt with a 5mm allen. A 19mm socket is required to turn the engine over CCW. Turn until the timing marks line up inside the small hole




2. Use some tape to protect the frame over the CCT. First remove the inner bolt, toward the middle of the engine. 



3. Here I will suggest you to go an extra step. Removing the RH side cover will make sure the chain doesn't skip a tooth and it will make it much easier to adjust the chain. I use my plier and some duct tape on the tip of the pliers to gently wedge between the engine case and the CCT slider. 




4. You can now remove the last bolt from the CCT.

5. It is now time to slide your new CCT In. Make sure the adjuster is all the way out. It won't go it if not all the way out. You can use the 2 bolts to hold the gasket in place then make sure the adjuster sit against the engine properly and start the bolts by hand and tight them up. 



Our bike are relatively new now so the chain should not be stretch too much with a lot of variation. 

All you have left is to bring the jam nut against the adjuster and tight it up. Make sure the adjuster do not move. Keep holding the adjuster with the allen key. 

There are also aftermarket Manual Cam Chain Tensioners for sale (below ACT version), these allow you to set the slack of your timing chain manually, keep in mind Automatic Cam chain tensioners tend to fail over time, so most likely you will end up doing this job yourself. To do this, follow exactly the same steps as showed before, the main difference being that you would need to get a feel for the slack of your timing chain, which is not the easiest thing in the world for a newbie or a mechanics savvy to do, without previous advises.