I used to go on a forum for my car a lot, and one common mod that people liked to do was grounding kits, or upgrading the electrical grounding.
I upgraded the original ground wire on my 250ex a while ago with a larger gauge and it definitely seemed to make an improvement.
Today I added a larger gauge, shorter length ground wire to my 400ex.
I used a 2 gauge piece of wire about 18" long, crimped on some copper terminals and put some heat shrink tubing on it.
It looks like a store bought piece to me...
I attached one end to the ground on the battery, and then routed the wire around to the mount for the tool box. I sanded the paint down on the frame to make a good connection, and tightened everything down.
At start up, it fired much quicker (even with my weaker battery,) the neutral light was obviously much brighter, and it seemed to idle much smoother.
Total cost was about 8 bucks, and about an hour of time.
It's not a huge upgrade, but I feel getting more potential out of my battery was worth it.
AC Nerfs - Swingarm Skid + Honda Racing Skid - Protaper Contour Bars - Rox 2" Riser - CBR Clutch Perch - Oury Grips - HT Moto Seat Cover - Custom Poly Case Saver - TRX450R Front Shocks - XR250R CDI - YFZ 450 Dual Piston Front Calipers - ITP T9 Baja Rear + GBC X-Rex - CanAm DS450 Front Rims +Holeshot SR Front - Dominator Bumper - UNI Filter - 13/39 Gearing - DID x-ring Chain
AC Racing Nerfs - Oury Grips - Fmf Slip-on - Uni Filter - Razr Rears