Dirt Demon Solutions

The following procedures are provided as solutions to certain problems associated with the Dirt Demon. Hot Bodies understands that there are many customers who thoroughly enjoy the Dirt Demon, most of whom are extremely knowledgeable about R/C nitro cars. These procedures are provided for informational purposes only. Hot Bodies takes no responsibility for their implementation or any problems resulting from implementation. Only highly knowledgeable, technically skilled owners should attempt these solutions. These procedures are courtesy of Andrew OíBannon and Brandon Foisy: Hot Bodies Customer Service/Tech Reps.


Front and Rear Differential Shimming:
This procedure prevents problems from arising in the front and rear differentials, and usually improves performance if no problems are evident.
-remove the diff pinion from case
-remove out drive from pinion
-remove shims (2) from pinion
-re-install shims between the bearing and the out drive
-re-install diff pinion assembly into case and screw case back together
-spin out drive by hand, checking for smoothness
if the diff catches on one spot or still appears rough, add third shim
between outdrive and bearing
note: you can add a third shim if available or use a glow plug washer in place of
all three shims.


Double Spur Gear Conversion:
One problem affecting Dirt Demon owners stems from the thinness of the spur gear. This can cause the clutch bell to strip. Doubling up on the spur gear generally prevents this. This procedure should only be attempted by owners comfortable with power tools. Follow all safety procedures associated with any tools used.
1. strip chassis of everything except the transmission and top plate
2. remove brake, out drive and bulkhead to loosen screws holding spur gear
(use number 1 phillips screw driver or you may strip the screws). Add second spur gear and reinstall screws
3. take the brake bulkhead and sand numbs almost flush (not flush or you will
run into screw holes!)
4. Sand the lip that keeps the bearing from going through so that the bearing still fits
snug but can be pushed all the way through from either side
5. reinstall the brake bulkhead with the sanded nub side towards the spur gear (this
means that the bulkhead is turned around 180 degrees from original position).
6. put screws and brake pads back on and install the brake out drive and disk
7. spin the spur gears to check for clearance between brake bulkhead and spurs
8. if rubbing occurs, sand more material as needed until desired fit is obtained
9. now that the brake bulkhead has been turned around, installation of the brake
and top plate will cause the brake cam to be tilted at an angle as a result of the
off-center hole drilled in the brake bulkhead.
10. you must ìoval-outî the hole in the brake bulkhead to allow the brake cam to seat at a 90 degree angle to the bulkhead and top plate
11. to allow full braking, you must add a small piece of material (approximately
6mmx6mm, 3mm thick) to the face of the brake cam to increase the overall
width to get full brake actuation. Use CA or a 5 minute epoxy to bond the material to the cam
12. when completed, the transmission is done. You must now grind the chassis
and top plate to allow room for the width of the extra spur gear
13. begin with the chassis, grinding until a comfortable fit is obtained, then the
top plate. It may take several attempts of grinding and checking clearances with
the transmission to get a good fit.
14. when completed, reassemble.


Bullet Proof Jump Start:
Some owners have problems with one-way bearings slipping or cracking. One way to ensure this does not happen is to use an HB11311 RTR3 backplate set with gears. In this set you will find the big main gear with a larger hex then that of the Dirt Demonís main starter gear. By using this gear with an HPI #1669 one-way bearing (larger than the DD bearing) and inserting them into the Dirt Demon backplate, you should not have any more problems with slipping or cracking.