overpressure


6 replies to this topic
  • waipuk78

Posted October 28, 2009 - 07:04 PM

#1

Have just done a full rebuild of my 05 yz450f and have noticed that the radiator pressurizes and dumps a lot of coolant after about 20 mins of quite hard riding the cooland was no longer visible in the tank any ideas?

  • rufusz

Posted October 29, 2009 - 01:43 AM

#2

Head gasket?

  • devo1

Posted October 29, 2009 - 08:30 AM

#3

Have just done a full rebuild of my 05 yz450f and have noticed that the radiator pressurizes and dumps a lot of coolant after about 20 mins of quite hard riding the cooland was no longer visible in the tank any ideas?

I have the same problem after a rebuild. I'm suspecting the head gasket too. With the cap off and running higher rpms i start to see air bubbles.:smirk:

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

Posted October 29, 2009 - 08:37 AM

#4

You can test for the presence of combustion gases in the cooling system. Most good shops should be able to do this, or an inexpensive kit can be bought to do it with.

How did you gentlemen torque your head bolts?

  • ForsheeMS

Posted October 29, 2009 - 08:57 AM

#5

Did you have the cylinder and head mating surfaces checked for flatness?

As Gray said, the torque method for the Yamaha's is rather unusual but it works. If you didn't follow the proper torque method I would suspect that is your problem.

  • waipuk78

Posted October 30, 2009 - 10:04 PM

#6

I didnt put the head back on but Will it be ok to loosen off the retourque using yamahas method

  • grayracer513

Posted October 30, 2009 - 10:28 PM

#7

... the torque method for the Yamaha's is rather unusual but it works.

It's still a bit unusual in the motorcycling world , but it's been evolving into the standard in the automotive world for the last twenty years or so.

I didnt put the head back on but Will it be ok to loosen off the retourque using yamahas method

I might work, but if the gasket's been leaking, there's less chance of it. May be worth trying.





Related Content

Forums
Photo

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
Forums
Photo

James Stewart back on a YZ450F by YamaLink


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies
Forums
Photo

2016 YZ450 by CaptainKnobby


Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies
Forums
Photo

Snake pit oct 30th by The Anvil


Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 replies
Forums
Photo

BIGBORE FOR YZ450F 2006? by Taattie94


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 3 replies
 
x

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.