I had an issue with my 13.5 today my car all of a sudden stopped moving and it the sounded like the pinion was loose. When I inspected it you could hold the shaft by the pinion gear and hear the motor turning inside. I disassembled the motor and found that magnet portion of the rotor was loose and could be spun on the shaft by hand. I put a new rotor in it and it was back to normal...The motor was never run over 140 deg and has about 17 runs on it 9 in 4 cell oval and 8 runs in my touring car anyone have any ideas on what may have caused this or could this be a defective rotor??? it is being sent to novak for an eval but I am curious if anyone else has expierienced a similar problem???/

This is a new one on me!

Which type of rotor was it? Black bonded? Gray bonded? Sintered?

I'm betting it's a gray bonded rotor. Happened alot with the 5800 motor, but I haven't seen it yet in a 13.5.

that happened at the roar carpet nats this year to someone not sure the guys name but it has happened?????

We had the same thing happen on the very first batch of the 5800's with the gray rotor. I saw the shaft fly out of the endbell.

I too have heard of it...but not yet with the 13.5's (was it sintered or bonded? What color was the rotor?)

It happened to both of my 5800's. I came up with a way to fix it (probably NOT Novak approved :D ). Make a mark on the shaft so you know where the rotor should be, then pull the rotor off of the shaft. (Here's the un-approved part) Now take a hammer and make a bunch of dents in the shaft where the rotor goes. (Seriously.) But DON'T whack it hard enough to bend the shaft! This also makes bumps next to the dents. Now press the rotor back on to the mark you made. Some Loctite wouldn't hurt, either.

Of course, another way to fix it is to buy a sintered rotor.

Sounds like too much work. Just buy a new rotor. If it's new send it back to novak they take care of it.

It happened to both of my 5800's. I came up with a way to fix it (probably NOT Novak approved :D ). Make a mark on the shaft so you know where the rotor should be, then pull the rotor off of the shaft. (Here's the un-approved part) Now take a hammer and make a bunch of dents in the shaft where the rotor goes. (Seriously.) But DON'T whack it hard enough to bend the shaft! This also makes bumps next to the dents. Now press the rotor back on to the mark you made. Some Loctite wouldn't hurt, either.

Of course, another way to fix it is to buy a sintered rotor.


That sounds like a great idea!

Here's what I'd try........

Go to the Hobby shop and buy some 1/8" music wire. Put it in the oven at 495 degrees Fair-in-height for 12.5 hours to harden the wire.
Cut it at the appropriate length while it's still hot. Be careful, it's hot.
Also, while it's still hot, pound about 3/8" flat spot for your pinion set screw landing area.
Here's the tricky part....
Go to the refrigerator and collect all of the magnets you can find. Look in the junk drawer if you cannot find at least 8 oz. of magnet material. Put the magnet material in a small oven safe pot or bowl. Set the oven temp as high as it will go and wait for the magnet material to melt. Stir the material toghether so it is a smooth yet pastey [pastie] but not runny.
let it cool slightly.
When it's cool enough to pick up with asbestos gloves roll it in your hands until it is about a 13mm tube. Cut into lengths about 1.25 inches. While it's still warm insert a music wire section as closely to the middle of your magnet roll as possible.
WA-LA! You got yerself a brand new brushless rotor for about $1. The cost of the music wire. Refrigerator magnets should be free. If your paying for your refrigerator magnets, you're shopping in the wrong stores.

I hope this helps.:)

:freak: Ummm....That was a joke, right?

i think scotts been drinkin somethin other than coffee!!!!!!!!!!!

It happened to both of my 5800's. I came up with a way to fix it (probably NOT Novak approved :D ). Make a mark on the shaft so you know where the rotor should be, then pull the rotor off of the shaft. (Here's the un-approved part) Now take a hammer and make a bunch of dents in the shaft where the rotor goes. (Seriously.) But DON'T whack it hard enough to bend the shaft! This also makes bumps next to the dents. Now press the rotor back on to the mark you made. Some Loctite wouldn't hurt, either.

Of course, another way to fix it is to buy a sintered rotor.



Kevinm is right !!! I have done it and used Loctite high temperature sleeve retainer ( just a little) and it works great. :thumbsup:

i think scotts been drinkin somethin other than coffee!!!!!!!!!!!

Hi Mike! We are missin' you back here in the cold cold wilderness.

ya miss you guys too, but 75 and sunny is hard to beat. plus i have 8 different rc tracks close to my house, within 30 miles most are 15 or less.

Well, it's good to know your "gettin' by" out there.

ya i'm roughen it!!!!!!!!!!

:freak: Ummm....That was a joke, right?
I certainly HOPE so. Unless he's been drinking the Paragon again....