burgman proud said:
* "Using Manual mode, especially when on interstates with high sustained speeds" This is a
quote from the knowledge base on this link Please explain why this is a factor in lessening the wear on the stopper bolt please?
Tony.
The items listed in the BKB as ways to minimize wear are mainly just things folks have speculated might help. There really is nothing to say they will help other than that. I'll talk a little more about the design of the primary pully assembly to maybe explain it a little more.
This assembly is what I would describe as a shaft within a shaft design. There are three shafts moving at different speeds relative to each other. Innermost is the shaft for the primary pulley. The primary pulley is hard geared directly to the crankshaft on the engine and it turns continually in one direction as long as the engine is running. The pulley’s speed is proportional to the speed of the engine. Over that shaft is fitted another shaft that I would describe as a hollow bolt. The inside fits over the primary pulley shaft and the outside is threaded. This shaft is not suppose to move and is located in place by the primary pulley stopper bolt. Over this is another shaft that I would describe as a big nut. The inside is threaded to screw in and out on the hollow bolt shaft. This nut has bearing surfaces that push and pull on the moveable face of the primary pulley to change the gear ratio. It is turned by the CVT controller motor and can turn in either direction. It is geared to the CVT controller motor by a series of reduction gears and moves relatively slowly.
There are two sources for load on the end of the pulley stopper bolt, one is weak and the other is stronger. The weak force is caused by parasitic drag through the bearings that separate the primary pulley from the “nut and bolt” adjuster assembly. The stronger force comes from the CVT controller motor turning the adjuster. Think of it this way.
Assume you are holding the whole primary pulley assemble in your hand with your thumb in the slot that the stopper bolt normally goes into. Take your other hand and turn the pulley. You will feel a slight force against your thumb in the slot but it is not very strong. This force is cause by parasitic drag through the bearing surfaces.
Now take your other hand and turn the gear that connects to the CVT controller motor. You will feel a much stronger force against your thumb in the slot. This is just like when you try to tighten a nut and bolt. You need two wrenches, one to hole the head of the bolt in place and one to turn the nut. In this case, the pulley stopper bolt is the wrench holding the bolt head and the CVT controller motor is the wrench turning the nut.
You can see from this description that the things that would cause wear on the end of the stopper bolt are things that cause the CVT controller motor to try to turn the adjuster. Each time the CVT control motor tries to turn the adjuster you get a hit on the end of the bolt. These hits can be on either side of the bolt because the CVT control motor can turn in either direction to open or close the adjuster.
If you are running along on the highway with the transmission locked in OD then the adjuster is not moving so the load on the end of the bolt should be minimized. Conversely if you are using manual mode to shift gears I would suspect that wear on the bolt is increased because you are doing a sudden relatively large change in gear ratios each time you shift up or down. This would put a sudden high load on the stopper bolt. Same thing would probably occur when you shift in and out of power mode. Running in auto mode would cause a lot more changes in ratios but they would be smaller and softer so you’re getting a trade off of more hits but each less likely to cause damage.
I don’t see how jack rabbit starts would have much impact. The controller would have already shifted the CVT to its lowest ratio before you started moving so the only hit on the stopper bolt would be the lighter parasitic drag through the bearings. Sudden acceleration while you are moving like speeding up to pass a car would be a different thing though. If you are in auto mode and you suddenly opened the throttle the CVT controller would do a quick downshift to a lower ratio. That sudden downshift would put a load on the stopper bolt.