Could someone tell me how to tell if I have a bonded or sintered rotor? I have a novak 13.5(not ss) that I tore down to pm and found the rotor to have 2 chips missing out of rotor. I suspect the front bearing may have got some debris in it as it turns a little rougher now. Which rotor would be better for offroad super stock class, so when I order a new one I get the right one. I need to order a front bearing also. Is rc4less a good place to deal with for the bearing? Thx. for the help.

Anybody?

Is it black or silver?

Black is bonded. Silver is sintered.

also does the front end bell have the large or small bearing?

Looks black to me. And the end near the pinon has the larger bearing from what I remember. Should there be a shim on the (rear) connection side? When I tore it down there was 3 on the front, but none on the other end. Thx.

no shims on the tail end( sensor end) if its a black bonded rotor it should be the small bearing.

All the Novak sintered rotors (#5908)
have a hole drilled in the pinion shaft.
Have a solid shaft with the larger 5mm diameter neck leading to the pinion shaft for use of the oversized bearing
Do not use shims
Have been plated in nickle and should have a "chrome" finish"

If the rotor is black or grey it is not a sintered rotor. Some black rotors have the pinion shaft drilled. So without opening the motor one can not be 100% positive on a used or old motor. All the new motors now have a chamfered (belved) edge where the motor mounts along with color id rings for the stock motors.

A nearly foolproof and uninvasive way to check for a sintered rotor is just twist the shaft by hand and if the rotor wants to lock into place like brushed motors due then the it is sintered. A bonded rotor will still hold inplace, but does not "lock" into place.

mt 17.5, 10.5 and 13.5 ALL have shims on the front end to reduce play and came that way from novak.

I am positive it is black. It was a used system that I bought a year ago or so. It does have a hole drilled near the pinion. So this must be a bonded rotor. Should I buy the sintered rotor? Is it better? Or just buy a ss version? I would hate to put to much money in this motor and still have a bad motor. Thx.

Sintered rotors stand more heat than bonded. Motor produces more power with this rotor as well.

Great Thx for the help

you will need the rotor kit for your older motor. it will come with a new endbell with the "bigger" bearing.

If it has a black rotor, you probably don't need the endbell kit. Check the size of the bearing on the output shaft end. If it's 3/16" I.D., all you need is the sintered rotor (unless the existing bearing is bad).