2002 yz426f

3 replies to this topic
  • hartatak

Posted March 31, 2014 - 01:56 PM


Hey guys I'm new here and also new to the 4stroke mx club. After years of owning 2 smokers I bought a yz426. The thing needs a carb rebuild for sure, which I'm capable of doing myself. But the one thing I'm not sure of is a glowing red hot header. I took it for a spin around my block last night and noticed it glowing all the way from the head to just about the end of the heat shield. I've seen some posts saying that it's normal, but it doesn't seem right to me. I mean there's never been a pic in a magazine of some guy in a sx race with a red hot header. I only mention that because I'm sure those guys are riding their bikes harder than I have. Any suggestions?

  • lkeffersyz

Posted March 31, 2014 - 01:58 PM


Yeah I have the same exact bike its got thin titanium header pipe they all glow red at dark
No problem just make sure is not running lean

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  • grayracer513

Posted March 31, 2014 - 02:39 PM


It's entirely normal.  Red heat visible in low light indicates a temperature of around 800 ℉.  The normal exhaust gas temperature is in the range of 1200-1400, and can run higher if the timing's retarded as it is at an idle in neutral.  If you were to go a little faster, convective cooling from the outside air would take most of the red away.

  • hartatak

Posted March 31, 2014 - 03:35 PM


Good to know thanks guys

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