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XR400 Header Pipes Glow

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The header pipes on my XR400 have always run really hot and even glow a cherry red color at night. I have checked the color of spark plug numerous times to see if the motor was running a little lean but the color of the spark plug is tan/light brown not white. The 400 has been running strong for the past 10 years with no indication there is a problem and there is no popping sound during decellaration. Is this normal for most XR400s out there or does it vary?

Thanks in advance for any feedback and/or advice.

John

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It's not uncommon to see this. It's a little concerning if you've never noticed it before. Just make sure you're jetting isn't too lean and you're running the right spark plug. A little rich on the jetting is better than a little lean.

To rule out a lean condition tho( besides just reading the plug),Wouldn't hurt to check your fuel screw setting and retune it. Make sure it's not being set more than 3 turns out to attain best idle(on the rich side). If it is, your pilot jet is too small.

Do you know what your current main and pilot jets sizes are? Tell of any intake and exhaust mods done to the bike. Your elevation.

If all this turns out to be what's expected, then you can chalk up the glow as just the nature of the beast.

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I don't know what size jets I am running. I bought the bike used in 03. The guy I bought it from raced so I assumed he knew what he was doing and changed the jets when he installed the Yoshimura exhaust and K&N air filter. The bike has always run good so I never bothered checking the jets in the carb. I am not even sure if it is the stock bore. I just happen to notice the color of the header pipes recently when I was running the bike after dark. I did check the spark plug and since it was not a white color I thought for sure I didn't have a issue with it being too lean. It has been running with the same jets for at least 10 years. I think if it was too lean I would have fried something in the motor by now.

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So in the 8 years you've owned it the carb has never been off.

You're probably right, it's fine and the glow is just something you've never noticed because of never having run it after dark.

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2 hours ago, Chris Berglund said:

My 2000 Honda  xr400r header pipe is cherry red 

I'm gonna try to help you out here Chris. First, if you were to take just a little more time writing about the issues you are experiencing, we as a group might be able to help you a little more than the one sentence statements you keep making on threads that are YEARS OLD- Start a new thread, with a descriptive title, then some detail into what you have going on in the body of the post. DETAILS will help others give you an answer to your questions. 

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13 minutes ago, redhurricane said:

I'm gonna try to help you out here Chris. First, if you were to take just a little more time writing about the issues you are experiencing, we as a group might be able to help you a little more than the one sentence statements you keep making on threads that are YEARS OLD- Start a new thread, with a descriptive title, then some detail into what you have going on in the body of the post. DETAILS will help others give you an answer to your questions. 

 That's all I know about the dirt bike I don't know how to start a new thread

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42 minutes ago, Chris Berglund said:

 That's all I know about the dirt bike I don't know how to start a new thread

At the top of the thread list on the right side, there is a red button you click to start a new thread.

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52 minutes ago, Chris Berglund said:

 That's all I know about the dirt bike I don't know how to start a new thread

Hope this helps. Big red button on the top right side, this is in the XR250/XR400 forum.

 

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