Situation: Maybe your old e-gyro esc burned out, you own a vmx450 and want an e-gyro upgrade kit, or you just purchased a new MM450 without an e-gyro esc.
The MM450 and E-gyro upgrade kit used to include a 30A esc. Unfortunately that apparently had issues in manufacturing and so was pulled from the bike and kit. The status of the original gyro esc is unknown. Atomik is now selling the bike (and e-gyro kit) without a gyro esc for the time being. On the website for the bike, under “Required Items” it lists “50A Brushless ESC for eGyro.” They have a tech sheet with information on what sort of esc you can buy, which is basically a plane/heli esc with soft startup feature. You can view the PDF “MM450 Without Gyro Instructions” under the documents tab at http://www.atomik-rc.com/Metal-Mulisha-Brian-Deegan-MM450-RC-Dirtbike-ARR_2.html?sc=31&category=76730
(NOTE: Its not clear why Atomik changed the Amps on the ESC requirements from 30 to 50, but owners of 30A ESC’s have reported no issues. So if you can find a cheaper 30A ESC with same soft start ramp up, its up to you but worth considering.)
The big difference between the original gyro esc and buying a plane/heli esc is that the original had a built in ramp-up of the gyro to full speed so no other signal was required to fire that up. As far as I know, a regular plane/heli esc can’t do that by itself so it requires either a servo tester, or use 3rd or 4th channel on receiver and a radio to start the gyro ramping up. If you only have a 3ch radio and want to install a front brake kit that uses ch3, then a servo tester is your only option. If you have a 4ch system, then you can still run the front brake on ch3 and control the e-gyro on ch4. Your radio will have to support this sort of channel control, which is mentioned in the tech sheet if you follow link.
Find a no frils, small, simple tester which should only cost about $10. Here are some options for servo testers to look for that should work:
– ESKY Rc Hobby Servo Tester
– Hobbyking Simple Servo Tester
Wiring of E-gyro ESC:
– 3 wires out: connect to the e-gyro stator motor with 3.5mm bullet connectors
– 2 wires in: for pos/neg power use 3.5 bullet connectors. If not already setup (you have a VMX), you will need to soldier outgoing pos/neg wires from your power source, like the main bike ESC pos/neg with same 3.5 bullets that will connect to the gyro esc power wires.
– 3 pin connector: either plugs into your main radio receiver, ch3 or ch4, or into the servo tester for control signal.
Wiring of Servo Tester:
– Power in: hard to say what design you get but the servo tester will have either a small 3 pin design for power or actual pos/neg wires option so you need to bring power in to give servo tester power.
– 3 pin Signal Out: you will connect the gyro esc 3 pin receiver connector into the servo tester. This sends out the proper signal from tester to the gyro esc, which tells the gyro motor to start spinning!
Final Check: gyro flywheel should spin the same direction as the rear wheel to go forward. If gyro is spinning wrong direction switch up 2 of the 3 wires going from gyro esc to the gyro stator. Hope this helps.
Photos by: Mitch Landry and David Hourston. Thanks guys!