08 YZ450 overheating - Yamaha Forum : Your Yamaha Motor Products Community & Resource
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post #1 of 12 (permalink) Old 02-25-2010, 08:21 PM Thread Starter
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08 YZ450 overheating

Hi guys, so i am new to this whole forum thing. My rommie says they are all the rage. I have a 08yz450 that has not been ridden in 5 months. I recently pulled it out of my trailer and started the bike planning to ride. After it was running for about 2 min the header pipe turned bright red it was so hot. I have never seen my bike do this ever. I did the obvious thing and checked my coolent levels and the hoses and everything is fine? Then in my inspection i found that something has eatten away at my case. its only on the front, every other part of it is fine. Now my friends yz125 sits right next to my bike and we ride together all the time and his bike is fine. Any ideas would be greatly appericated.
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post #2 of 12 (permalink) Old 02-26-2010, 07:49 AM
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That is corrosion because it is made of magnesium, and the protective coating was scraped off during normal use.

I actually was not aware they made those covers out of magnesium , kind of surprising really.

The corrosion resistance of magnesium or magnesium parts depends on similar factors that are critical to other metals. However, because of the electrochemical activity of magnesium, the relative importance of some factors is greatly amplified.
KEY to METALS Articles: Corrosion of Magnesium and Magnesium Alloys


Galvanic corrosion - Wikipedia, the free encyclopedia

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post #3 of 12 (permalink) Old 02-26-2010, 07:54 AM
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in regards to the header, due to the timing of the yz and the material the head pipe is made of they do glow red when left to idle a while.

if you are concerned double check to make sure there is no overheating issues and check fluid levels.

It is possible that you have never noticed the glowing of the head pipe because you usually start the bike in direct sunlight.

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post #4 of 12 (permalink) Old 02-27-2010, 05:12 PM Thread Starter
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Thanks for the info. I had a couple people tell that was normal for the bike to do that, but like you said i mostly ride durning the day and have never noticed that.
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post #5 of 12 (permalink) Old 04-22-2010, 09:47 AM
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red header

i noticed the glowing header on my 250f after cleaning the carb, i was running it in my garage got a little concerned too.

Last edited by moose; 04-22-2010 at 11:19 AM.
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post #6 of 12 (permalink) Old 04-25-2010, 10:30 PM
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The color of the pipe is an indicator of what is going on also in your engine.
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post #7 of 12 (permalink) Old 04-26-2010, 04:34 AM
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Originally Posted by itsmygame View Post
The color of the pipe is an indicator of what is going on also in your engine.
Yes, I guess , but every one will do it if you start your bike in the shade of a garage or ever at night you will see it on any mx/f model.

it is because the material the pipe is made of and the timing of the bike itself .

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post #8 of 12 (permalink) Old 07-09-2010, 08:28 AM
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On the 4stroke it's totally normal for the pipe to get so hot it glows if your just sitting at idle on a stand or such. As far as the clutch cover there it look the me like a gasket needs to be changed either on the cover or maybe the oring for the oil filter cover. Check the torque on those and maybe it's time for some new gaskets.
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post #9 of 12 (permalink) Old 08-16-2010, 01:36 PM
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I have the '09 yz450 and I'm sure it gets red if you turn down the lights. My crf450 did. Really surprised me one night when I was running it night before a ride in garage. But the corrosion is pretty far along on your bike. I'd spend a day cleaning, lubing and giving her some TLC dude.
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post #10 of 12 (permalink) Old 12-01-2010, 03:51 PM
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After about 2 min your pipe should not glow red if your in a lit area. Chech the rest of the exaust temp by feeling your tail pipe. If your tail pipe is to hot to touch after a short amount of time your bike may be running to lean. If the bike is poping alot then you will also know the mixture is to lean. This happend with my bike, the exaust was so hot it melted my air box. Check your fuel mixture jet at the bottum of the carb. The further you unthread the more rich you will make your mixture. Carefull as to not unthread it to far as it may fall out during riding. This should bring the exaust temp down when you enrich the mixture, if not you may have to change your starter jet.

Last edited by Yamadog11; 12-01-2010 at 03:53 PM.
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post #11 of 12 (permalink) Old 11-23-2014, 04:38 PM
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2009 YZ450F overheating?!?

Hi everyone.my names alex. I'm new to yamaha forums. I recently bought a 2009 yzf 450f. I started the bike up the other day and noticed minutes later the the header pipe off the motor was glowing red. Iv looked around a bit and notice that it's fine. But when I went inside I notice out the window the bike was smoking out of the radiator hose under the bike. Also liquid was coming out i assume it's coolent. I wanna know if thats normal or is there something I need to do. The owner before me put a aftermarket radiator that was bigger for trail riding. Let me know what anyone thinks. Thanks
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post #12 of 12 (permalink) Old 11-25-2014, 03:50 PM
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is the hose is leaking or melted?

the glowing header will always happen after several minutes in idle. Warming the bike while riding is a better procedure than waiting for it to reach operational temperatures in the shade or where ever, because the bike is overheating without air flowing through the radiator core.
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