Motor Problems

we built a six-bar & the motors will not run at the same speed & keep jamming on something we can’t find. what do we do?

Without more detail, there is not much we could do to help. If you could post pictures, it would be great.

If you could provide more details or a picture of the 6-bar, we could provide more specific answers. From previous experience all vex motors are different and perform at varying degrees, so there is the possibility that you have a “weaker” or “stronger” motor on one side or another. This can happen with old motors or even happen with brand new motors. Don’t forget to check that all the motors have the same internal gearing, as well. Also, check each motor one by one to see if they are running in the same direction.

In terms of what mechanical changes you should make, I would recommend linking the left and right side with two coupled axles. Make sure that you link the two sides with gears that have the least amount of torque. The coupler is included with all new motors, and I don’t think it can be purchased separately.
Linked Mogo Lift.jpg
On our old mogo lift, we had a 12:36 gear ratio and linked the 12 tooth gears since they supported the least amount of torque.This ensures that this long axel is not subject to a lot of torque which will lead to a twisted axle. This also helps the motors run in sync, if you have a “weaker” or “stronger” motor issue that I described earlier. Also, if you suspect that the 6-bar is hitting something, check if you have screw heads hitting something because those are often overlooked.

As far as software control, the easiest thing to do would be to reduce the motor power for one side and increase it on the other side. This solution is not the best, but it provides a quick fix.