Quad cuts out when giving half throttle in gear.
Hey guys Im new the forum, thanks for having me. I have problem with my 03 kfx 400 cutting out when you put it in gear. It sounds like your hitting the rev limiter. I did what member Normal Z posted back in 2009 which is,
"Here's what you can do - and you can make it all temp right now to test it out. It'll work, I guarantee, but you might not like it if you do any clutchless shifting, ever. Like, EVER. Basic details first, then the pic:
4 wires going to the Gear Position Sensor (GPS): Red, White, Blue, Black.
Reverse: Red wire, connects to Black/red wire through the connector.
Neutral: Blue wire, connects to Blue/black wire through the conncetor.
Any Forward Gear: White wire, connects to Black/brown wire through the connector.
Black wire connects to the Black/white ground wire through the connector. Conducts ground for the sensor.
The Neutral, Reverse, and Forward Gear wires use the sensor position to conduct ground. When the sensor is in one of those gears, ground is made, and the CDI does what it does. When the sensor is in between any of those circuits (when you're shifting) there is no ground on any of those 3 circuits at all, so the CDI cuts spark.
The White wire, at the sensor, which connects to Black/brown going to the CDI - that wire doesn't go anywhere else on the bike. It only connects that electrical path.
The Reverse and Neutral wires only go to the CDI and to their indicator lamps. I've got a way for you to keep those lamps working...
AT the CDI connector - right at the connector, you'll have to remove the pins for those two circuits. Remove the pin for the Black/red wire, and remove the pin for the Blue/black wire. That will prevent the CDI from receiving the signals from Reverse and Neutral. The lights will still work when you're in one of those gears, but that signal doesn't get to the CDI. No reverse rev limit now. Some aftermarket CDIs have a Neutral rev limit - that'll be gone, too.
Now, you have to trick the CDI into thinking it's in a forward gear, no matter what gear it's in, and even if it's not in a gear at all, just like when you're between shifts, and the GPS is between contacts...
At the connector for the GPS, you'll have to remove the pin for the Any Forward Gear wire - the Black/brown wire. You're going to temporarily ground this. Use a piece of wire wrapped aroung the pin, bolt the other end to a motor case bolt, whatever. Make a temp ground. At this point, the CDI will always have constant ground on the "Any Forward Gear" circuit, and there will be no more spark interrupt. None at all. Your N and R lights on the dash will work, no reverse rev limit, no cutting of spark by the CDI anymore, and the possibility of trans gear damage on clutchless shifts - that's what you'll gain by doing this. Once you test it, you can make that Black/brown wire-to-ground a permanent fix.
NOTE - make sure you tape up the pins on the CDI connector wires that you remove - if you don't, and they accidentally hit metal and make a ground, your Neutral or Reverse light on the dash will be flashing everytime they make contact... "
That fixed the problem it runs normal now. I was wondering if there was any way to fix the problem correctly, without grounding the wire. Do I need a new gear position sensor?
Any help or info would be greatly appreciated.
Last edited by tparker85; 04-22-2012 at 09:03 AM.