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2014 YZ450 Exhaust pipe glowing red at idle?


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i just switched from a 2013 yz to a 2014 yz450 brand new i started it last night for the first time and at idle with cold start pulled out right a away the first 8 to 10 inches of the pipe was glowing reg, i know that pipes do that but i just didnt expect to see that at an idle and so much of the pipe. just wanted to know if you guys thought that was normal?

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That will help if he had fmf or aftermarket exhaust.

 

No, it applies directly here. And the threads referenced were not about cooling, they are about glowing exhausts specifically.  It also applies directly to stock exhaust pipes, since the factory header is the same high grade, thin wall titanium that the aftermarket uses.  It has nothing whatsoever to do with the cooling system, either, as the pipe isn't cooled by that system, and the cooling system has very little overall effect on the heat of combustion at an idle, nor on exhaust temperatures at that speed.  Header construction plays a part in this; lighter pipes will glow more readily because it takes less to heat them.  Mine glows with the factory Ti header, but not with the heavier stainless pipe I run with.

 

The glow indicates that the pipe has reached about 8-900 ℉.  The source of the heat is, of course exhaust gas, which normally runs at temperatures around 1300 ℉ under "cruising" loads, and up around 1650-1800 ℉ at full throttle.  The reason the pipe doesn't glow at those times is simply due to the convective cooling done by the air flowing over the moving bike.  The exhaust temps are higher than normal at an idle on the YZ450 because of its relatively high idle speed, very aggressive cam timing, and the retarded ignition timing at an idle.  Add to this, it's an EFI bike, so the fuel system will keep the mixture rich as long as the coolant temperature is lower than the normal operating range, even if the "choke" is off.   It's really pretty normal overall, and although there are different degrees of it, it's very seldom anything at all that anyone should worry about.

 

 best thing to do is just read up on a lot of this stuff.

 

 

Good advice.  You might want to follow it.

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I'd say the only thing it wouldn't be that may be a factor is fuel tuning. Lean motors run hot I had a yz 125 burn the piston because the oil in it got cold and clogged the carb. Therefore little to no oil and little gas that was the only time if ever seen a 2 stroke overheat. Be careful with fuel to air ratios!ImageUploadedByThumper Talk1394214346.457197.jpg

~Yz426F&Crf250R~

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I'd say the only thing it wouldn't be that may be a factor is fuel tuning. Lean motors run hot I had a yz 125 burn the piston because the oil in it got cold and clogged the carb. Therefore little to no oil and little gas that was the only time if ever seen a 2 stroke overheat. Be careful with fuel to air ratios!📎ImageUploadedByThumper Talk1394214346.457197.jpg

~Yz426F&Crf250R~

 

And, of course, it did that while it was idling with the header glowing red, right?

 

Not relevant.

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