426 Losing Coolant

2 replies to this topic

Posted March 23, 2005 - 07:53 PM


My 2001 yz426 is losing excessive coolant out the overfow hose. I just bought a new radiator cap but I am still losing coolant. The bike isn't overheating though. My FMF pipe runs really close to the radiator, could this be the problem. I have also cleaned the whole system and there wasn't any blockages.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • grayracer513

Posted March 24, 2005 - 10:33 AM


If you're losing coolant while sitting at idle, and you're idling longer than about a minute, it's not abnormal. There's no air flow over the radiators, and the circulation within the engine is slowed way down. Try to keep it moving as much as possible. Even just bouncing the revs up a little once in a while will help, but not as much as air on the radiators does.

If the overflow occurs under way, it may be a head gasket leaking into the cooling system, or it may actually be overheating.

  • Dano426

Posted March 24, 2005 - 11:12 AM


Like grayracer513 said keep it moving. I trail ride with my 426 and turn off they bike when waitings for the kids. It also helps to use a coolaint aditive like water wetter or a better coolaint. I am currenlty using engine ice

Related Content


100 hrs on 2014 yz450f, shim valves or replace them? by ttr230rider6

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  79 replies

Need help by Goforaride

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  68 replies

Michigan Motocross Tires by 288yz450

Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply

yz400f throttle bog by yz400fmaniac

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • * * * * *
  • Hot  28 replies

yz250x vs 450 4t comparisons (preferably desert riding) needed by JakeNorthrupYZ450F

Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • 9 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.