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Gearloose
2002.04.13, 10:27 AM
Hi guys!

I just installed a Top Racing balldiff (equal to Eagle Racing?) and yes, the car is very stable and easy to drive with it. But, Iīm experiencing that the car is loosing torque as well as topspeed. A bit slow.

Of course Iīve tried a lot of settings on the diff, both hard and loose and anything in between.

Do you feel the same way with Kyosho original b.d. or is it just my brand that is low quality?
One thing is for sure; the car is much more quiet.

Searched the forums for this one but didīnt find anything really.


(Sorry for my poor english, Iīm from Sweden. Hope its OK)

petersiu007
2002.04.13, 11:18 AM
Maybe it's not slower. It sound strange, but because it's much easier to drive and quieter, it may just SEEM slower. Just a thought.. hehe;)

Mondo
2002.04.13, 11:29 AM
Gearloose,

Read this Thread:

http://mini-zracer.com/forums/showthread.php?s=&threadid=1422

Ding! and another one:

http://mini-zracer.com/forums/showthread.php?s=&threadid=847

Anyway, I have both TopCAD and Kyosho units.
Fuctionally they are the same, quality wise, Kyosho beats the TopCAD on quality, there is NO comparison. Of course, the Kyosho comes at a premium price, but in my opinion, worth every penny.

Check the following:

Is the ball-diff tension collar overtight?
Are the pinion and spur gears meshing correctly?
Is the diff left hub too tight against the motor mount? (I leave about 0.25mm space between the hub and motor mount bearing)

I suggest TopCAD ball-diff units be stripped, examined for bad anodising [a known problem the TC units] cleaned, lightly greased and re-assembled.

Gearloose
2002.04.13, 02:34 PM
Thnkx!

Think I have to dissasemble the unit and do some finish on it.
It also shipped with one thin tiny washer and thanks to the links I figured out where to put it.

Iīll let you know.

herman
2002.04.15, 02:59 AM
or maybe you just need to clean your motor... noticed that my two cars were really slow (one even had a turbo in it)... cleaned the motor (with motor cleaning spray - available at any hobby shop)... and it was back to normal... hope this helps...:D

Gearloose
2002.04.15, 04:16 AM
Cleaning the motor can make a big difference!

I also dissasembled the ball diff and sandpapered (Uggh! I dont know the word for it):confused: the balldiff-shaft which was extremely tight fittened to the ball bearings.
Now there is just enough space for the shaft to rotate without too much tension to the bearings.
This seemes to help much. And, like Mondo suggested, I now have increased the space between the left hub and the motormount.

But finally, the TopRacing unit I got seemed to have just a little too thick shaft. So I adjusting that seemes to have solved the problem.


(My friends; what is the english word I should have used above: When I use a paper with sand (or another rough surface) to shape a piece of material? Sandpaper? Sandpapering? polish? grind?.... Canīt find my dictionary!)

greetings
Gearloose from Sweden

Mondo
2002.04.15, 04:58 AM
Gearloose,

Sandpaper it is.
I put my TopCAD ball-diff shaft into my Dremel tool and gave it a good sanding too. Like you, I also found the shaft was tight when fitting it through the motor mount bearings.

I am glad it has helped resolve your problem.

herman
2002.04.15, 05:02 AM
gearloose,

good to hear that your car is running better...

(My friends; what is the english word I should have used above: When I use a paper with sand (or another rough surface) to shape a piece of material? Sandpaper? Sandpapering? polish? grind?.... Canīt find my dictionary!)

hmm... how about, smoothened the shaft with sandpaper? aurgh.. sanded the shaft? reduced the diameter of the shaft by sanding? oh well... anybody else?

enjoy your mini-z :D