Need brush and comm advice
 

Last week at the track noticed the motor was real hot so pulled the motor and put a different one in to finish the night. Do the brushes look bad you can tell they were hot and what do you think about the comm. CO27 stock motor with 18/86 gear

http://img.photobucket.com/albums/v6...6/DSCF0045.jpg

http://img.photobucket.com/albums/v6...6/DSCF0049.jpg

Fordman yes those look like they got hot but I have seen lots worse. Could be lots of reasons why it happened and can't tell from the pic's. Cut the comm and replace the brushes and make sure every thing is free in the motor and in the turck and all should be well. From the picture it does not look like you are over brushed which could make it run hot and 18/86 should be fine with a stock motor in a truck. Just keep an eye on it next time out.

I run mine at 18/86 in a mf2. What tranny do you have? Gen I or Gen II?

Just a wild guess, but from what I see, I'd say the brush springs were too soft, letting brush bounce create extra heat. Not enough to "harm", but enough to affect performance. Assuming you were running offroad, there is a lot of extra vibration and bouncing going on -- brush bounce can quickly over heat a comm. The color change on the comm and brushes clearly show heat, but your gearing doesn't sound out of range at all -- I've run that gearing range locally offroad with no problems at all, but with heavy springs (like Red/Red or Purple/Red)

gen 1 tranny stock mf1. I run red/green now might try the red/red or purple/red. On the purple/red what is the + side purple? also there 767 brushes.

Correct +Purple -red

When I ran elect offroad I ran +pruple -red in both stock & 19t with 767's or 4499's.

thanks for the info might have to give them a try. Now that I bought a lathe can true up the comm when I need to.