yz400 or wr400 cdi?

I need some help I bought a yz400f a couple of months ago, it wasa basket case but had a Ca Plate so it was worth it. Anyway, alot of parts on the bike are WR parts, like the stator. I also recieved a box of extra parts, in it is the yz stator, and an additional CDI.

I now have a new engine top to bottom, and a Carb off a yz426, and it is finally running decent after the new carb, jd jetting and disconnection of the TPS sensor.

The only problem I am left with is sometimes I am running fast on a freeway or in traffic and the bike will all of a sudden cutout, like someone cut the lightswitch momentarily. I am guessing an electrical issue, but JD said I might be running a WR CDI and that might be the problem, but both CDI boxes I have look the same , how do I tell the difference between a WR box and a YZ box?

no takers?

AFAIK, a WR CDI will not work on a YZ stator and Vice versa. A WR CDI is powered by DC, the YZ, AC. JD is talking of the famous 'WR Stutter' Not a cutting out.

I am running a wr stator for sure, so you are saying that my cdi must be a WR? Would the YZ CDI even plug into the WR wireing? I am just a bit stuck.

Aslo tell me more about the wr stutter?

The earlier WR's (98-02) CDI runs on AC like the YZ so it is interchangeable. The 2 6-pin plugs will plug in fine, however the WR CDI will have another 2-pin plug with a black/white (I think) and grey wire (yes, the notorious one) in it, whereas the YZ will have just a single bullet on a black/white wire. The black/white wire is the kill switch, short it to ground and it kills the engine. For testing purposes you wouldn't even need to connect it up, just as long as you don't mind stalling it to kill it :worthy:.

thanks that is what I needed to know, this bikee is driving me a bit nuts. At this point I have a bike that runs clean down low and way up top, not so much in the mid range, it sort of coughs. But at least after disconnecting the tps it now starts easily. We are tryig the clip in a different position to see if any improvement can be had.

So, I also have a plated 98 yz400f and just recently installed a modified 98 wr400f stator and flywheel. The cdi unit is still from the yz, but now the bike won't start at all. I've read how a modified wr stator will work with a yz cdi unit in these forums, i am finding that isn't my case. Baja designs (maker of the light kit on my bike) has told me i need the wr cdi unit as well, but that's a pricey little number. They also said i didn't need to modify the wr stator. Is my issue the cdi unit or could there be something else wrong?

I bought the stator used and it showed up modified already. I got one yellow lead from the stator going to the regulator/rectifier and the other yellow lead from the stator going to the chasis. The cdi unit hooked up to the stator just fine. Any ideas why the bike won't start? Will installing the the wr cdi unit still work since the stator was modified? Please help, I want to get back to riding!

okay, I wound up disconnecting the TPS sensor and it solved most of my issues. My suggestion is to try this, also feel free to give me a call at 530 200 6458, I have an extra CDI maybe I could sell it to you for you to try.

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