well i had always backed them up because i love the white bros racing stuff, but finally i was let down...ive been noticing recently on my 416 that the battery was dragging and it wasnt wanting to start at all and even a lil hesitations./.....i was getting worried, so i remembered peeps had said something about the white bros rev kits gone bad, so i took it off and put my stock back on and guess what....it runs perfect, no hesitations and starts up in one try.....i called nacs and they are sending me a new one...they said white bros supposidly has fixed this problem and i would get a non faulty one..has anyone had this problem and got a good one in return......thanks

 

I wonder if it is actually a problem with White Brothers' CDI or if it is a problem with all high rev CDIs for the 400EX. The reason I say this is because all of the high rev CDIs are nothing more than stock Honda CDIs that are intended for the XR250. White Bros. or (fill in the blank) just buys them from Honda and then slaps their part number on it and sells it. It is highly doubtful that White Bros or anyother parts shop is having special CDI's made per their own specs.

 

SINCE THE TIMING IS BEING ADVANCED FROM THE WB/CDI AND THE OIL IS THICKER DUE TO THE COLD IT'S HARD FOR THE BIKE TO TURNOVER AS EASY. WHEN IT GETS WARM OUT DROP IN THE WB/CDI AND IT SHOULD FIRE RIGHT UP.

 

To be real honest with you they are a real waste of money anyway they rev way past the powerband of that motor anyway.Dont waist your time or money with one get your money back 4 strokes arent known for high rpm power anyway unless its a yz 426 and they are time bombs ask a few guys who have raced them they dont stay together eastcoast atv puts the 426 motor on the 400ex and they are blowing them up left and right the fourstroke is known for good mid and low end. besides where we ride the modified bikes dont run much faster than the stock ones they just spin alot more they feel alot faster but arent covering anymore ground. I have a 400 ex and a 400 scrambler 400ex all stock the scrambler has pipe reeds roller helix clutch kit carb and we went riding the scrambler in a drag race will beat my 400 ex by about 4 bike lengths but in the woods and trails they are even sometimes the ex even gets the jump because it doesnt spin as bad and as far as jumping goes the honda kills the tank i mean the scrambler I have a friend that has a radar gun and i have ran my scrambler on it and ran 70.6 mph and the ex ran 64.6 We also ran the raptor on it it wouldnt brake 70 mph my friend has a LT500 it ran the fastest at 71mph and it out ran the raptor and its not the rider we switched off riders and go the same results in the woods is where the rider comes into play.I have been messing with this stuff since i was around 11 and im very picky about what i buy and ill do my own testing on it Im not bias i stick to what works thats where a $1500. radar gun comes in handy get you a gps they are pretty acurate which we have even tested them comparing them to the radar gun they are nearly perfect.

 

i have to beg to differ....the rev kit makes a noticable difference....when i sent my other back i had to ride with stock cdi....i could tell a noticable difference in my revs, and it kept cutting out really quick....well i just got my new cdi and its working awesome....my gears seem allot longer, and pulling even harder with no cutting out on the rev limiter.....