Cherry red header pipe

Okay I have a 2009 yz250f I took off the carb and installed a intake boot on it and cleaned the carb put everything back as taken off. Bike wouldn't idle and had a miss to it took hot start loose from handle bar and pulled it through frame instead of taking it loose at carb. After putting back together fired it up and it now idles. Took it down the road and back and looked and header was cherry red..I did take gas feed cables loose what could be my problem I never noticed it doing this until I fixed it today.

Red header=lean from every thing that I've heard.

Is it possible that re routing the hot start cable is keeping the plunger from fully seating? Does it appear to operate correctly? Air leak at the new boot maybe?

Was it dark when you noticed this? Headers will normally turn red a little bit but it's more apparent at night.

Edited by Thumbster21

Yea it is real red at night I think your right about hot start I will check it when I can get a min. Just kinda worried me it started out it wouldn't idle at all got that fixed but think my hot start is the problem. Thanks thumbster21 for the help

No problem. I've got an 09 also that I've taken apart more times than I care to count.

Do you like the 09 how reliable is it. Does the header on yours glow to

Is yours a 450 or 250? I saw some of your other posts that said you had a 450 but this thread you said it's a 250.

Either way, yes I like my 250F. It Is my first real dirt bike.

I got it a year ago and it was not in the best of shape. Not far from being a parts bike. I've been fixing it up slowly and am pretty much finished at this point.

They are easy to work on and have the reputation of being bulletproof. Parts are readily available due to their popularity.

Mine is reliable now that I've worked out the bugs that the previous owner(s) have created. Basically it was neglected but I've kind of enjoyed reading through the owners manual and forums like this to get the information needed to fix it back up.

My header does not glow. At least not enough to be noticeable. I spend most of my time going slow in 1st or 2nd gear though.

Did you get a manual for it? That tells you just about everything you need to know and if you can't find it there I use this forum.

Edited by Thumbster21

450

Was the header cherry red right after you parked it or was it after idling for a little bit of time. The header getting cherry red when idling stationary for some time is normal but it should not happen while the bike is moving. If it is happening right after the bike was moving say less than a minute or two then its likely it is running lean. How does the bike run? Does it backfire a lot on decel? some popping is normal but not an excessive amount, if it is backfiring then try running the bike with the choke on, if it improves then it is definitely lean. 

It's not unusual to be able to see the red at night.  Tune the bike by how it runs, not by the color of the exhaust pipe in the dark.

Tmeyer37 I had been adjusting the idle on it because it didn't idle at all. I didn't even check the pipe I got idle adjusted and rode it about 100 yards real slow and looked down and noticed it and shut the bike off. I will be replaceing the clutch basket then I will work on watching how the header does. Thanks everyone for the help

With a normal, healthy, stock YZ250F or YZ450F with the OEM titanium header will turn the header a visible red in low light such as the typical garage, or twilight.  Happens all the time.  That equates to a temperature of about 800 ℉, which isn't at all surprising considering that the pipe is barely .040" thick and normal exhaust temps at idle run around 1400 ℉.

With a normal, healthy, stock YZ250F or YZ450F with the OEM titanium header will turn the header a visible red in low light such as the typical garage, or twilight.  Happens all the time.  That equates to a temperature of about 800 ℉, which isn't at all surprising considering that the pipe is barely .040" thick and normal exhaust temps at idle run around 1400 ℉.

Thanks my friend

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