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View Full Version : Yokomo MR-4BC/B-Max 4 spur modification.


Dingbat
01-02-2011, 06:23 PM
Lately I have been having problems sourcing spares for the old yoko MR-4 BC,
namely spur gears to fit the slipper clutch.
Anyhow one day I bought a B-max 4 spur gear just to see the difference.

It turned out the spur is near identical bar the hole size through the center.
The B-max has a larger hole through it. 13MM diameter to be exact.
Whereas the MR-4BC spur fits on the 10mm diameter slipper shaft.

B-max parts are readily available,so I decided to make a simple adapter.
See pic's.

No1,after turning some alluminium stock down to 13MM diameter,
and drilling a 10MM diameter hole through I set up the dremmel to
cut off the adapter ring.
(My little lathe Is not very good and parting off is a definite no/no
hence dremmeling)




http://i51.photobucket.com/albums/f394/cosmickjack/DSC00060-1.jpg


No2 The modified B-max spur.

http://i51.photobucket.com/albums/f394/cosmickjack/DSC00064-2.jpg


No3 Installed spur and slipper pads.


http://i51.photobucket.com/albums/f394/cosmickjack/DSC00065-2.jpg




No4 Ready for installation.

http://i51.photobucket.com/albums/f394/cosmickjack/DSC00066-1.jpg





Hopefully someone somewhere will find this of some use.
Db.

fastinfastout
04-02-2011, 04:00 AM
wouldn't it be easier to get a cat sx spur which is 8mm, and just drill it out to 10mm.

Dingbat
04-02-2011, 07:12 AM
It would be If the slipper pads were the same.:p

fastinfastout
04-02-2011, 09:32 AM
not the same?

I was pretty sure I have used AE slipper pads in both bmax and cat spurs before

Dingbat
04-02-2011, 04:57 PM
not the same?

I was pretty sure I have used AE slipper pads in both bmax and cat spurs before

Fair one,
unfortunately for me I didn't have access to any other slipper pads or spur gears to try.:)

Bikerbob
11-03-2011, 04:08 AM
Do you fellows know anyone with an extra slipper unit??

I need one for my BC.. we are running on industrial carpet and I need the slipper to save the drive train.

I am in S. Ontario Canada.. Yokomo does not exist here.

Any ideas for me with this buggy?

thanks

james

91notch5.0
11-03-2011, 04:17 PM
bikerbob....i feel your pain. i ran a yr4-m2usa when sedan racing was at its best. loved the car but will never own another yok. i worked at a hobbyshop and parts were a pain. customer service was terrible too. since then, ae and losi only for me.

Bikerbob
12-03-2011, 03:25 PM
Crazy eh?

Largest RC market in the World? and Yokomo USA is shut down.. almost a year ago now.

I have to say I wonder why Horizon or Great Planes have not tried to pick it up.

Maybe Yokomo themselves are not a big player anymore and dont wish to fight it out in the NA market?

On the otherhand - small players like Caster and Durango and going gang busters over here.

James