Bearhawk Cooked Brand New Sports Tuned Motor

[brisbaneracer 0]

  Hey everyone, i was racing my bearhawk on dirt and gravel, when the motor stoped working towards the end of the batterys life, the motor was way too hot to touch and doesnt turn anymore. its screwed. The No limit speed controller is working fine and normal temperature, and the battery is ok aswell. What would cause this brand new motor to do this, im pretty sure the pinion im using is the stock one, its a bit worn, the chassis rolls freely and is fitted with ball bearings and a motor heatsink.

[brisbaneracer 0]

  I suspect the Gearing is to blame, im going to buy the lowest tooth pinion gear i can, Im not entirely sure, but will this hop up option fit the Bearhawk and its spur gear?

Tamiya 12T , 13T HP Steel Pinion Gear Set #53063

The pinion gear i was using that is slightly worn now, is a 15 tooth

Much appreciated

[Scorpn 18]

Sounds a bit strange, I used sport tuned, super stock, dynarun stock, technigold and a few Le Mans motors in my Bearhawk and never had a worry, raced them and everything - the Bearhawk is limited to a choice of 15T or 17T so you are running the lowest gearing available - What were you doing with it?, If you were really straining the motor, like pushing stuff or towing stuff? it could strain the motor, was it really dusty?, the sport tuned runs bronze bushes and they could bind if dusty enough?

 

[brisbaneracer 0]

  Thanks for your reply scorpn, it was dusty conditions, i wasnt doing any towing. I was racing it up and down a dirt hill, there was lots of wheel spin because i had blazing star wheels and tires on the back becacuse i need new vintage 4 pin hubs for my spiked wheels. Could this have been the reason for its demise?

[mr_pushrod 5]

When you say it doesn't turn, is that at all or not under power? Could always have been a bit of dirt or gravel that got jammed between the com and the can.

[brisbaneracer 0]

  It doesn't turn under power, but its free to spin with your hand, it feels like there is friction and it has lost the feel it had when it was new.

[mr_pushrod 5]

Looking in to the motor, can you see any obvious damage to the com or brushes? Ideally you would need to open it up to investigate but it's very hard with a sealed can motor. This is why I like rebuildable stocks and mods over a sports tuned, most of the time you can repair them easily.

[brisbaneracer 0]

  looking inside, the brushes have about 2mm left at the thickest part, i don't know how the rest of its ment to look, Thanks allot for your input mr_pushrod

[kontemax 1734]

Maybe something wrong on the motor or gearcase.

Anyway you can fit smaller pinion gears to bear hawk (15T instead of 17T and 13T instead of 15T) buying Blitzer Beetle gears. They seem perfecly equal but they don't. Blitzer Beetle spur gear is 1tooth bigger and the second gear is 1 tooth smaller is I remember well. This is due the bigger wheels. If you put these gear cen mount pinion gears 2 teeth smaller without mods. Also you can fit hotter motors.

Max

[Scorpn 18]

Don't you need to buy the Blitzer gearbox case as well - I think the bigger spur rubs on the bearhawk one? Glenn

[theshopkeeper 43]

Sounds like a duff motor to me, you can usually run these (sealed) motors right down to the metal brush holders. Bit of dust not usually an issue.

[kontemax 1734]

Obviously the bear hawk gears perfecly fit the blitzer beetle gearbox and reverse. You only need to buy the spare gears to obtain a longer (low) or shorted (high) gear ratio on your cars.

Cheers

MAx

[brisbaneracer 0]

So can somebody reassure me, ive heard conflicting reports, so Blitzer beetle Gears (RC Stadium Blitzer Gear Set Item #50453 ) WILL fit into the bear hawk gear case, to then fit a smaller pinion such as (TAMIYA BUGGY PINION GEAR SET 50238) ??

[kontemax 1734]

Reassure:

Why the motor gone cooked?

1 - Defective motor

2 - Extremelly hot weather

3 - Running on grass

4 - Problems in the gearbox, or generally in the transmission (have you the ball bearings inside?)

5 - Too much low gear ratio (it can be due bigger wheels too)

One solution for low gear ratio (also called long): open you gearbox, remove all Bear Hawk gears and substitude them with Blitzer Beetle gears (you can note them because the name on the gears is different. Count the teeth, the number is different.) Then remove the pinon gear. You can use 2 teeth smaller pinion gears with Blitzer Beetle gears. So your 17T will become a 15T and your 15T will became a 13T. This will shorten your gear ratio (also called High ratio) avoiding the cooking.

If the problem is in the other points you must serch the solution in another way.

Cheers

Max

[brisbaneracer 0]

 It was hot weather, it was dusty, there was grass, thats about it, the gearbox has good ball bearings, and the chassis without the motor in it rolls smoothly. I can't imagine using the stock pinion with a Sport tuned motor being too hot. The only thing i was iffy about the car was the worn pinion gear, but it wasnt that bad. Im really not very keen to change the spur gear and others to blitzer beetle. I cannot see anything wrong with the current gears, they run smooth and it has a new diff. there are ball bearings throughout and i made a custom alloy motor plate with a cooling fin and the motor has a heatsink too. i guess ill use the stock can motor that i get with my new TA05 this week and monitor its temperature carefully, i was reading about breaking in stock motors in a jar of water with a 3v power supply. here is the url. Is this a good idea? it doesnt say how long to run the submerged motor for, im interested too know if this is a common technique.

Cheers

[kontemax 1734]

OK, grass, hot... this is the reason. Trow away the original 17T pinon gear and buy a 15T pinion gear, better if it's a steel one (more rpm, no wear). 15T is better for the Sport Tuned motor.

Second, there's an error in this page. On the paper hard brush ruins quicker the commutator. In reality this is false. Hard brush prevent commutator wear because there's less friction.

Soft brushes made more friction on the commutator cause they are abrasive so the commutator ruins faster. But this is not your problem with Sport Tuned.

I prepared the silvercan motors in the beer instead the water because the beer is harder and made more resistance. The rotation of motor in the beer (or water) must be reversed for the break in. The motor will be faster in the correct rotation. Forget your silver can after this treatment. Magnetic fields in the beers will oxide the can. The motor will look worse than new.

[Rabiedmushroom 2]

You're kidding me... right?

You get a brand new standard motor, hook it up to some normal batteries to make it run backwards, and dangle it in a jar of water or beer for a bit. And it magically makes it runs faster? And it doesn't damage or swamp it?

I like the idea of the beer option. You can drink a spare whilst you are waiting []

[DJTheo 2]

That in-fluid running-in is only for stock can motors and was mainly used by racers in the past, but not really needed with modern motors and with hot motors the wear will be extreme, check terry.scs posts at http://tamiyaclub.com/CS/forums/thread/167965.aspx http://tamiyaclub.com/CS/forums/thread/36381.aspx

http://tamiyaclub.com/CS/forums/thread/18550.aspx

http://tamiyaclub.com/CS/forums/thread/168736.aspx

Cheers

[kontemax 1734]

It's not a joke. Try and see.

[ukzz4iroc 3]

Sure you probably knew this but hey its advice

Make sure you are using the 2 corrfect motor mount holes for your pinion- otherwise it meshes too tight and can overheat the motor.

Cheers