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Glowing header?

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Just started my bike (06 kx450f) for the first time in a coup months, and my entire exhaust started glowing cherry red, to the point where it looked like it was going to collapse from the heat. It's an fmf 4.1 exhaust this has never happend before, even on the hottest days of the summer. Any ideas?

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If you let it idle for more than a couple of minutes, plus the lighting was dim, then that's perfectly normal. If you are still worried then try turning your fuel screw out a 1/4 or 1/2 a turn. But you should only care about how it runs on the track.

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I used to work at a Yamaha Dealership when the YZ400 came out and I remember when we got the first one prepped and ready to go it was dusk and when we fired it off the header glowed bright cherry red. The customer refused the bike until we had Yamaha speak with him directly to tell him it was OK. Titanium does this more then Stainless steel does and it's perfectly normal. You either never noticed it before or the pipe is new. Most aftermarket pipes are using thin titanium and therefore it shows up more then OEM but they ALL do it.

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Does your radiator have a fan?

No.

Will the motor get hot if you start it?

Yes.

Does the header dissipate heat from the motor, which is sitting still, without a fan, and radiators that are not doing their job...?

Yes.

Should you start any dirt bike with a radiator, not ride it, for more than 2 or 3 minutes?

No.

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Does your radiator have a fan?

No.

Will the motor get hot if you start it?

Yes.

Does the header dissipate heat from the motor, which is sitting still, without a fan, and radiators that are not doing their job...?

Yes.

Should you start any dirt bike with a radiator, not ride it, for more than 2 or 3 minutes?

No.

:lol:

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I always put a fan in front of my bike and let it run pushing air into the radiators, i do this everytime i start my bike. Ive noticed it helps keep it cooler while just idleing on the stand.

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I always put a fan in front of my bike and let it run pushing air into the radiators, i do this everytime i start my bike. Ive noticed it helps keep it cooler while just idleing on the stand.

If the purpose if idling is to get the engine up to temp, why would you get a fan on it to cool it down? To make the warming up take even longer?

That is so overkill, just let it idle for a minute or two until the top of the radiator is starting to get nice and warm, then ride it like normal.

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no i dont use a fan when im out riding, i use it when it just sits in the garage for more then a few mins idleing, like when im adjusting something or checking fluids, i dont use it when im going to ride, just in the garage when the bike isnt going to be moving, and i dont have it on it the whole time, usually i put it on after the bike is running for a minute or two.

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I use a fan when the bike is on a stand (when changing oil). Its funny that the service manuals tell you to let the bike idle "minimum 3 minutes" (YZ450) but most bikes will get pretty hot in that time span. Not to mention there is no subsequent warning "but do not let it idle until it goes BOOM". LOL

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The bike gives an audible warning before it goes boom.. Its the steam piping furiously out of the vent tube. If you cant regonize that as a warning to shut the bike off you deserve to have it go BOOM!

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The bike gives an audible warning before it goes boom.. Its the steam piping furiously out of the vent tube. If you cant regonize that as a warning to shut the bike off you deserve to have it go BOOM!

If the bike starts to overheat, it's too late. Shutting off the motor will make it WORSE! You should ride the bike and cool it down.

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Ive seen plenty of bikes boil over and they are still running fine, (several of mine included).

I agree with everything you say but we are just talking about different levels of overheating. If u kill it as soon as it spits a lil steam it will be just fine.. if u sit there and let it overheat for several minutes then you could have a problem.

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i have a 2012 kx450 and the exhaust glows at the head

I also have a 2012 kx450 and was cleaning it after the first ride and noticed the header started to glow after it idled for a bit. I was getting it warm so I could change the oil and about freaked until I read your post. This is my first 4 stroke and had no idea that's normal. It was in my garage so maybe thats why it stood out so much. Thanks!:bonk:

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