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Red hot exhaust after start?

By toofazt,
in YZ400F/426F/450F/450FX

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toofazt

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Hey, I have a 2003 YZ450 with Yoshimura head work and exhaust. I haven't road it in at least six months. I just started it up with the choke on and was letting it warm up. I noticed a strange smell and looked down to see the exhaust pipe coming off the engine was glowing red hot. I've never noticed this before... Also when I turned the fuel on the petcock was leaking a LITTLE bit, guessing it's just a dried up seal or something simple? Is it normal for the bike to get so hot in a minute of warming up?? Is there something I should check after letting the bike sit for so long? Thanks, Steve.

*EDIT* I just found this thread about the glowing exhuast. https://www.thumpertalk.com/forum/showthread.php?t=236304

The bike still smelled funny. Is there something I should be aware of if my bike was sitting for a while? :ride:

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AlkalineOne

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Hey, I have a 2003 YZ450 with Yoshimura head work and exhaust. I haven't road it in at least six months. I just started it up with the choke on and was letting it warm up. I noticed a strange smell and looked down to see the exhaust pipe coming off the engine was glowing red hot. I've never noticed this before... Also when I turned the fuel on the petcock was leaking a LITTLE bit, guessing it's just a dried up seal or something simple? Is it normal for the bike to get so hot in a minute of warming up?? Is there something I should check after letting the bike sit for so long? Thanks, Steve.

*EDIT* I just found this thread about the glowing exhuast. https://www.thumpertalk.com/forum/showthread.php?t=236304

The bike still smelled funny. Is there something I should be aware of if my bike was sitting for a while? :ride:

i had this happen to my 426... turned out to be a clogged jet...

how does it run?

i could defenetly tell something was wrong with mine when the bike spuddered with throttle opening

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mn519

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this was after less than a minute(30-40 sec) idleing with a yz290f. Dr. D ti pipe, hotcams.

if you want to check your pilot jet, you can try to rotate your carb enough to take the bottom large main jet acces off the bottom on the carb, and the pilot jet is located right in front of the main jet. not fun, but should be better than trying to pull the whole carb. you will need a VERY SMALL SHORT standard screw driver.

I havent done it that way myself, but thats how i was told to do it next time instead of pullin the whole carb out.

SSPX0237.jpg

SSPX0235.jpg

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Kyle Prior

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this was after less than a minute(30-40 sec) idleing with a yz290f. Dr. D ti pipe, hotcams.

if you want to check your pilot jet, you can try to rotate your carb enough to take the bottom large main jet acces off the bottom on the carb, and the pilot jet is located right in front of the main jet. not fun, but should be better than trying to pull the whole carb. you will need a VERY SMALL SHORT standard screw driver.

I havent done it that way myself, but thats how i was told to do it next time instead of pullin the whole carb out.

SSPX0237.jpg

SSPX0235.jpg

...I dare you to touch it...

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AlkalineOne

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this was after less than a minute(30-40 sec) idleing with a yz290f. Dr. D ti pipe, hotcams.

if you want to check your pilot jet, you can try to rotate your carb enough to take the bottom large main jet acces off the bottom on the carb, and the pilot jet is located right in front of the main jet. not fun, but should be better than trying to pull the whole carb. you will need a VERY SMALL SHORT standard screw driver.

I havent done it that way myself, but thats how i was told to do it next time instead of pullin the whole carb out.

SSPX0237.jpg

SSPX0235.jpg

interesting... my yz450f takes about 3 minutes to look like that...:ride:

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berudd

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Ummm, mine doesnt...

yes it will if left idling. like he said they all do.

i wish dealers would tell everyone that gets a new 4-stroke about this. but that assumes they know something about them to begin with

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Grand Master

grayracer513

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Ummm, mine doesnt...
If that's yours in your avatar, it looks like it has a heavier, possibly stainless steel header on it, which is much more difficult to heat to red. The OEM header, and Ti headers like the FMF, etc., in general, tend to be extremely thin (< 1mm, or .040"), and Titanium glows at a lower temperature than most stainless will. Like I said, it is, at least to some degree, normal.
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toofazt

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the ole "my header is hotter than your header thread"......:ride:

get the dogs and marshmellows out folks, it's party time.......:applause:

swap that petcock out before you blow up....:ride:

Lol, I already did get a new petcock. $20 bucks :ride:

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black_n_blue_thumper

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yes it will if left idling. like he said they all do.

i wish dealers would tell everyone that gets a new 4-stroke about this. but that assumes they know something about them to begin with

My dealer told me when I bought mine. They told my brother when he bought his( I was there) and they told my buddy when he got his (again I was there). However, I recieved calls from both my brother and my buddy asking me what the hell was wrong and if mine did that too.:ride: :ride: :ride::applause::naughty: So credit to my dealer, and shame on my friends for not paying attention.

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yamarider628

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Yep they all do it I had an 01 426 it did it! Got an 07 yesterday and it did the same! The choke acclerates this! Just means theres no air flow thorough your Radiators/ which inso facto cools the engine! If your working on it while its just idleing i just put a good fan infront of the bike and this will help w/ the heat:ride:

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