S-Tuned R/C
Fitting a Top Deck to your MR-4BC
Parts Needed
Yokomo Worlds Top Deck (ZS-003UDW) (this is the kit I used - I believe the Pro version (ZS-003UD) will also fit (it should include the battery mount parts), but I’m not sure about the Special deck (UDS), as that car has a different battery mount - check before buying) (The Pro has more material in the top deck, but the Worlds deck is still quite solid, and would save weight).
How To Fit It
The Worlds deck comes with a bag of all the Allen head screws you will need, and instructions - however I used the original BC phillips screws, along with a spare 12mm screw I found in my toolbox. You will need to remove the backbone, the backbone cover, the servo saver support, and the rear dust cover. You may also want to remove the front dust cover as well - I did. All these parts should come away from the chassis without the need for any further disassembly. Next, fit the upper deck and large central battery mount - don’t forget to insert the servo saver spacers, which aren’t mentioned in the instructions - you use a thick and a thin one on each servo saver post. I’ve no idea how the small rear battery mount fits into the equation - leave the standard large rear one on.
Benefits
1. Motor and pinion access is much easier
2. The antenna is held more securely
3. Steering lock less likely to be limited (unless you retain the front dust cover)
4. Lower parts count, shedding weight and adding simplicity
Disadvantages
1. You lose some weather protection
2. Errr... that’s it
Other Stuff
1. It looks cool - in my opinion
2. The car seems a little more torsionally stiff, which should improve responsiveness, but remove a little grip - that may not suit your driving style or track
3. Hopefully more air will circulate around the drivetrain and motor, cooling things down a bit