if you look at the pictures above and below and then I can try and help with the following description
so the CCT works by adjusting its axial length using a rotation of the lead screw under torsional spring pressure. the spring also ensures that it will not back drive the screw under the load of the cam chain. But if the spring fails there is nothing to stop the lead screw retracting to the fully in position.
the stopper mod involves fitting a length of bar [the stopper] inside the screw mechanism so as to limit the free travel backwords, but have no effect of the continued forward stroke which is the normal function of the Auto tensioning process.
The key is to cut the length of the stopper to the exact length ["A" on the sketch] to suit each cylinder of your bike, and to do this you have to measure the exact stroke which is used in normal operation, and then subtract a calculated amount to give a good working free play for the normal rev / thermal movement of the CCT.
you take the end off the Plunger, insert the stopper and put the plunger head back on, and the CCT will go in and out as normal, but is now limited on how far in it can go, and this will ensure you only get a rattle problem from a slightly loose cam chain on failure not a bent valve from a jumped tooth.
Simple
