Prop shaft spring & motor disc latch

[robbo]

From Phill Robinson.
Just a couple of things we find help that I hav,nt seen anyone else using.
1. With the propshaft we have to have a little end float, about 2mm. This results in the spur gear being misaligned with the pinion and also allows the drive flats on the bevel pinions to become partially disengaged. (This may be the cause of failure that one or two people have had with the new pinions).
The cure is to find a light compression spring, one from an old biro is fine. Fit this spring into the forward end of the propshaft inside the one way drive collar and allow it to seat on the inside of the one way housing. Doing this effectively pushes the propshaft back against the rear bearing and keeps everything in the correct position. The small amount of drag created has no effect on the efficiency of the transmission.
2. The motor disc can detatch itself from the mount if you hit something hard. You can cure this by making a small latch to pivot on the screw that attaches the tie rod to the motor mount. Make the latch so that it traps the motor mount flange and can be swung out the way to release the disc when you want to access the motor.

[Northy]

The spring seems like a good idea! ;D

Don't understand the latch though. Any pictures?
The std mod used to be to fit a screw and washer to the back of the disk to overlap onto the mount to stop it moving forward.

[robbo]

Sorry no photos, don,t know where Paul has put the digicam. If you think of the latch as a rectangular piece of alloy with a hole in the middle, this pivots as explained and can be rotated to trap the motor disc or rotated to allow its release. Phill.

[Cooper]

I think I get it...

I'll make something in paint if you want?

[robbo]

Yeah O.K. then I can confirm if its right. Phill.

[Cooper]

Like this?



ps: thanks for the alumium gearboxtop part you sold me at Montigny, it works excellent! (and my tamiya gears also )

[YoKoMo-MX4]

...one other thing (that I do not think I've seen mentioned anywhere else) regarding how to 'fix' the motor mount slippage would be this: Rough up the disk and clamp surfaces somehow. I know on other vehicles with this style of motor mount a little dremel action is needed. I don't think it would take much more than a few scores (scratches) with a hobby knife to put some 'burr' on the mating surfaces. TTech's official fix was to reduce the contact surfaces ... but I think that is less desirable than simply making the mating surfaces more 'friction prone' with a little effort.

Any thoughts?

'nuff said,
MX4

[robbo]

Ref latch query, painted image is correct, it only takes 30 minutes to make one up.
Regagds, Phill Robinson