'98 WR400 power tricks

Hello people. This is my 1st post, and I happen to be the proud owner of a '98 WR400. I was very impressed with the high revving power of my WR400(compared to my old XR500s I have owned) until I rode a '03 YZF450. Wow! I'm not looking to match the power of the new 450s, but would like to gain some top end that was taken away at the factory once the WR stickers went on.

Currently, the WR has a stock '99 YZF400 exhaust, and it was jetted accordingly. (seems like it needs work still) '99 YZF 400 seat and tank. So, everything else is stock.

I have been told about cutting this wire for the rev limiter, and cutting this wire to have the more aggressive YZF spark curve... but nobody seems to be able to tell me exactly, so that's why I am here. I feel it's not worth while to cut the wire for the rpm limiter as the engine seems to fall off well beofre the 11,000 rpm limit. I'll venture a guess at 8-9k. Am told to retard the exhaust cam one tooth to fix this.

Anyone got any advice on what I should do?


Steve Mercier

I have a 98'WR400 also. Take off the tank and cut the gray wire, big difference in power. A Power Now wakes up the low end along with a Tork valve for your exhaust. I think my aftermarket exhaust woke up the bike the most. I used to run the stock yz pipe on it, which made a big difference in power, but my DSP exhaust made a much bigger difference than the yz pipe.

Thanx guys for the tips so far, but what's a "Power Now" ??

Also, let's start from scratch as I am not edjumacated on the hop up tips found here.

Starters... which grey wire? What is it connected to? Simply cut it?

Thanx... now I'm off to the site you posted here.


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