2021 Yz250F red hot 🔥

[chrisvids]

Here's a little explanation for people. The bike was cold before the start. I pulled the cold start lever, started the bike. It was only idling for 30 seconds. Yes, the cold start increases RPM. This is to warm up the bike. I was surprised that the header was glowing so fast, so I took a video.

Yes, I understand the bike doesn't cool itself while sitting and idling, at least after the coolant heats up and needs airflow through the radiators. The whole point was to warm up the engine. If you've ever been dirtbiking, you'd know it's not uncommon for people to idle their bike for less than a minute. In fact, mx racers are revving their engines far longer at the starting gate.

This bike connects to my phone and displays the coolant temperature. I checked the temp right after this, and it was far below normal operating temperatures.

This was over a year ago, and the motor is still great. I suspect the reason why the header was glowing so bright was because this video was actually taken at night time, with the white wall reflecting florescent lighting. Illusion of sorts and it would never be visible during the day time.

[streetstomper]

I'd say she's running a bit lean

[ANTHONYHST]

Cold start is on. Blip the throttle to take it off

[bradymxr]

Of course it does that cause it’s in cold weather and just sitting there duh.. even the older ones did it to in cold weather it’s very noticeable.

[That_boyLuke]

Mine just started doing it, I noticed it at night too? Think we got the same issue? Kinda dont wanna blow up a 2024 yz250f 😭😭

[abzskismotors]

You got the choke in for to long twist the throttle forward it should let go of the choke

[TCsGoons]

Because you didn’t jet he bike after putting a newer exhaust gotta change the header too can’t just swap the rear pipe

[Shadookie]

Just got 2010 crf450x that does the same thing . Now im afraid to ride it

[JamesM-T]

It’s because you have choke on still lol