red header

4 replies to this topic
  • az426

Posted July 01, 2001 - 08:07 PM


hey there i am looking for some one who may have ran across this friend and i both got new 426's and all the sudden his bike is idling high and about 20-30 sec. later the header starts glowing red-very red.he did tell me that he overheated his on a ride waiting on an xr600 but didnt notice anything just let it cool down.haven't taken to dealer yet.

  • bjscheel

Posted July 01, 2001 - 09:03 PM


Your cdi is shot, i went through the same thing and it took a month for the dealer to figure it out and still didn't. Finally i took my cdi apart about three hours later i found that my main computer chip was cracked. I called yamaha and they said that is common but they dodn't warranty it. A new cdi is 225.00

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  • Bill

Posted July 02, 2001 - 02:46 AM


If the bike is popping when decellerating (lean), you may need to richen the jetting (pilot) or open the fuel screw. I'd try this before I went to the dealer and asked about the CDI.


99 WR400f, YZ timed, MX-Tech suspension, Scotts steering damper, White Bros E-Series (12 discs), tapered header and a/f. Kouba T-handle for the fuel screw. Works Connection billet throttle tube and frame guards. Cycra Pro-Bend, triple clamp mount handguards. Thumper Racing rad guards, Renthal Jimmy Button highs, YZ Tank and IMS seat, YZ number plate, odo removed, EKP, 48PJ, 175MJ at 500-1000' Thanks James Dean!

  • mcarp

Posted July 02, 2001 - 04:58 AM


I agree with Bill. My '00 WR had a high idle when brand new. The jetting was just waaay to lean. After bumping the screw out a bit, it helped. Ultimately going up at least one size on the pilot jet not only cured the problem, but now the bike is less prone to stalling, has more bottom ened power, etc.

To test this, have your buddy rev the bike a little in neutral so that the idle is high. Now put it in gear and let go of the clutch slightly, but not all the way--just enough to engage it and bog the motor (NO THROTTLE). Is the idle back down to where is should be? If so, it's lean. Now hit the gas and I bet the idle will raise again.

The CDI problems are only affecting a small number of owners. Jetting is the #1 reason why the bikes running condition may not be ideal.

  • teamtoxic

Posted July 02, 2001 - 11:17 AM


<font color="navy">First things first: Did you play with the idle adjustment at all, not knowing what it was? That could be a problem. Check in your manual and make sure the idle is at factory settings.

Also, with the choke on, the bike idles faster. Make sure you turn that off.

If it's not just these simple adjustments, then check into what the other guys are saying about it.

A glowing header is normal on these bikes. It's usually most noticable in the dark. Almost everyone on TT has commented about the red-hot glowing header.


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