Left side of handle bars is for the reverse and rear brake. The rear brake is not important because there is also a foot pedal for that but the reverse requires that lever and the reverse cable.
Right side handle bar lever is for the front brake.
At one point you could get these cable through motion pro and they were sold by 223 Cycles in Tn.
If not available you might try ebay.
As far as the battery cables you might have to get creative. Those can be made if necessary.
Put your butt on the inside fender or end up on the ground!
TRX450ER
ATC250SX
ATC350X
ATC110
ATC185S
XR100R
CRF230F
Raptor 125
Breeze 125
Grizzly700