07 YZ450F Leaking clear/yellow fluid from bottom right of engine.

3 replies to this topic
  • jpf566

Posted May 07, 2013 - 09:12 AM


Hey Everyone! Well my worst nightmare came true. Just bought a bike on craigslist, didn't notice any issues when inspecting it. I got it home and it's leaking a Clear/Yellow fluid fairly rapidly when running. I've read around a bit and I think it's coolant. There is a gasket and a hole of some sort (maybe the weep hole? I've heard it referenced but don't know where it is) that seems to be leaking. I've read some posts saying the engine could be overheating if you're having coolant leaks, other said something about a water pump gasket...I'm lost and not sure how to procede

See Picture https://www.dropbox....si5yqte/450.jpg

1. Any Idea what would cause this?
2. Is it normal for that gasket to stick out like that?

Thanks for any help you guys can give!

Edited by jpf566, May 07, 2013 - 09:12 AM.

  • grayracer513

Posted May 07, 2013 - 09:35 AM


You have a leaking water pump seal. The hole is an escape port intended to allow coolant or oil that leaks past the respective seals to escape top the outside, rather than contaminating the cooling or oiling systems with the wrong fluid. Read:


And also:


Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • jpf566

Posted May 07, 2013 - 09:45 AM


thank you so much for your help! The top end of the engine has supposedly just been redone, if there is an issue with too high of compression could that be the root cause?

Just trying to make sure I don't replace the water pump seal and realize I have a much bigger problem

Edited by jpf566, May 07, 2013 - 09:47 AM.

  • grayracer513

Posted May 07, 2013 - 10:11 AM


... if there is an issue with too high of compression could that be the root cause?

Nope. The only compression related cooling system problems (apart from just the extra heat) would be with a leaking head gasket, which should still even then not have caused this, and would have shown other symptoms. By the looks of the stain, it's been doing this for a while, and it's not an uncommon leak. Reading through the first post I linked to should provide all necessary info on the procedure and the things to inspect.

Related Content


2016 YZ450 by CaptainKnobby

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies

Michigan Motocross Tires by 288yz450

Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply

First Hare scramble tips by dhend8

Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • Hot  33 replies

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

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.