98 YZ400F Carb Conversion

[transamman101]

Hello, I am new here everone. I just got a 98 yz400f and she had some carb issues. I cleaned it and reuilt it but still had issues. So I took the advice of this thread and got a 03 yz450f carb with the hot start cable. Should the 03 yz450f carb work well with this bike?

[namaher1]

I have a 98 yz400 and just got through putting a 2007 yz450 carb on it. The conversion is definitely worth it. Overall better throttle response and the bike is just so much smoother, it wakes it up. From what I've heard, a 2003 will work fine. I'm pretty sure you will have to get the 03 throttle cables also but they will work with your original throttle.

[transamman101]

the throttle cables came with the carb along with the twist tube. It seemed to install pretty easily, but there is still some problems with the bike. I noticed there is a electrical connector up by the front of the engine inbetween the head and radiator with four wires. Except 3 of the wires have been cutt. What does these four wire go to?

[namaher1]

the throttle cables came with the carb along with the twist tube. It seemed to install pretty easily, but there is still some problems with the bike. I noticed there is a electrical connector up by the front of the engine inbetween the head and radiator with four wires. Except 3 of the wires have been cutt. What does these four wire go to?

They are for either the neutral switch or the stator. You can just follow where they go to tell for sure. Do they look like a clean cut or rubbed through and broke?

[transamman101]

They look like a clean even cut.I believe the connector they go to is connected to the wiring for the stator.

[grayracer513]

The bike may actually be a WR400, or you may have a YZ400 engine in a WR, or who knows what other combo.  The cut off leads could be lighting.

[transamman101]

Well does the yz wiring harness connector that's connects to the stator wiring harness have four wires or less?

[namaher1]

Well does the yz wiring harness connector that's connects to the stator wiring harness have four wires or less?

I'm pretty sure the stator wiring connector has at least 5 wires so that is more than likely the neutral switch. Will the bike run?

[transamman101]

I can't get it to fire up, so no.

[grayracer513]

Wiring diagrams:

 

YZ400 first (no lights) then WR400 (w/lights)