red hot exhaust on 426

14 replies to this topic
  • yamaha429

Posted November 29, 2011 - 09:23 PM


I let my 2001 yz 426f warm up on choke for about a min then idle of choke for about 5 min while getting boots on when i came back to my bike the exhaust was glowing pinkish red and coolent was dripping out of hose that ran down the side of my bike is there something wrong??


Posted November 29, 2011 - 09:26 PM


yah, you overheated the damn thing letting it idle.... they are meant to fly, not sit for extended periods of time!

  • yamaha429

Posted November 29, 2011 - 09:28 PM


so then its fine to ride

  • CRF100biker

Posted November 29, 2011 - 09:30 PM


yeah you can't leave a liquid cooled 4 stroke to sit idle. air needs to be flowing through the radiators to keep it cool. when i ride my 400 through the tight stuff when it's getting dark i can look down and see the pipe glowing. it goes away when the trail and the throttle opens up though. the coolant dripping was the coolant boiling over and going out the overflow due to excessive heat build up from little to no air going through the radiators.

  • yamaha429

Posted November 29, 2011 - 09:33 PM


ok cool just got this bike a couple months ago im glad its not broken

  • Nick Merrell

Posted November 29, 2011 - 09:40 PM


It'll be fine, just make sure to check your coolant level and refill if you need to.

  • RiderX

Posted November 29, 2011 - 09:41 PM



Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • knac0341

Posted November 29, 2011 - 09:52 PM


had the same problem with my rmz,it could be that the radiator cap is shot and is not sealing pressure in your system anymore.try a new rad. cap and try ice coolant instead

  • yamaha429

Posted November 29, 2011 - 09:54 PM


ok i will try that thanks


Posted November 29, 2011 - 11:53 PM


ok i will try that thanks

Your rad cap is probably 100% fine :lol: This is normal under the circumstances!

  • sgmartz

Posted November 30, 2011 - 12:01 AM


yeah 5 minutes is an insane amount of time to let a bike warm up!!!!

  • Steel Panther

Posted November 30, 2011 - 01:26 AM


a glowing header is completely normal for a 4 stroke in dim lighting, that is probably the most common question asked here on tt by new members. It also is normal for the bike to get a bit hot and drip out some coolant if it sits for too long. Check your coolant level when it has cooled off to make sure you haven't lost too much and you should be good to go.

  • singletrackfiend

Posted November 30, 2011 - 06:32 AM


I had the same bike and it would do the same exact thing. Now you can imagine how easily you can dent that header especially if you lay it over on a rock or tree root while riding a tight technical trail. Your cap is probably fine. If anything, check your jetting and make sure your not running too lean and do a coolant flush. Lots of coolant to choose from. Coolaid works great for me. Good luck.

  • mikewrf18

Posted November 30, 2011 - 06:46 AM


If you need to let your bike idle for an extended period of time, (and 5 minutes is what I'd call exstended) for maintenance, tuning and such, place a house fan in front of the rads to direct air into them. It needs moving air through the rads to keep the bike cool.

  • knac0341

Posted December 11, 2011 - 10:52 PM


good looking out bro, i m now running engine ice as i changed the radiator cap.already flushed fluid too.seems to be working, just at idle 4-5 minutes seems to heat up.must be normal. thanks bro

Related Content


Chubby dad, looking at bikes , First trip to the orange/black forum ! by Slow_ride

Dirt Bike   Make / Model Specific   KTM   250-530 EXC/MXC/SXC/XC-W/XCR-W (4-Strokes)
  • Hot  28 replies

05 yz450f not fast enough by RedeyeYZ

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  38 replies


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  30 replies

Should I buy this bike? help....... by Numsa Hul

Dirt Bike   General Dirt Bike Forums   What bike should I buy?
  • * * * * *
  • 10 replies

James Stewart back on a YZ450F by YamaLink

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.