Motor problems: Monster Stock

[eliseracer]

I bought a Monster Stock a few weeks ago and ran in about 8 times. For the time that it ran, I was thuroughly satisfied, until the day that it stopped running. At first, I was sure that it was the soldering job's fault, but now after I re-soldered it with new leads and new wiring, it still doesn't work. I tried cleaning it with motor spray, cleaned it until the run-off was clean. Then I went onto cleaning the brushes. They are ****-and-span and there is no sign of bad contact, or any other damages. I also troubleshooted the motor with various batteries, various ESCs and various radios but it still doesn't work. Rarely when I apply throttle and spin the pinion briskly, I get some power, but then when I release the throttle back to neutral, the motor stops working. I would doubt the comm needs to be cut because I ran it very little. There is no exterior visual damage of any sort. I really want my motor to work so that I can actually run my RCs, but for now I cant. (I also need new charger and batts :p)

[TEM]

Is the comm burnt? Take it apart, clean everything; cut the comm assemble it. Without the brushes in it, spin the shaft so you know it's freely spinning. Put in one brush and spring at a time and turn the shaft and check to see if the brush(es) are hung. Even ever-so-lightly hung brushes will make a motor not work! Then check continuity of the terminals. Should conduct. If your charger don't do motor test, hook the motor up to a 3-4cell pack(make sure the pack is good! test on a good motor if necessary). If it still don't work, email Trinity.

[eliseracer]

Yeah I just rebuilt it and it fixed it. Works good now.

[Grizzbob]

That's about what I thought, I know you'd think a stock motor would be fine for more than 8 runs, but in order to get the power they're now making they must sacrifice longetivity. On a typical race day, I'll maybe run a stock about 5 or 6 times max & then regardless of how it seems to be running I'll take it apart & do a complete rebuild. The longer a motor runs, the more its commutator wears, & that causes the brushes to start bouncing on it as it runs, which only makes the comm wear even worse. That's why many of us retrue the comm on a VERY regular basis(as I said, no more than 6 runs max, fewer than that if using very high-silver content brushes). And in the long run, rebuilding it that often actually makes the comm last longer than by running it quite a few more times between rebuilds, because with regular rebuilds, you don't need to remove nearly as much comm material from it to make it true again, & of course doing so religiously also has the benefit of keeping your motor running at its very best ALL the time....:cool: