2008 yz450f overheating bad


9 replies to this topic
  • yamie

Posted March 17, 2012 - 03:13 PM

#1

I checked the site before posting but couldn't find anything to help my problem, Since new, my 2008 yz450f has been overheating, even on the track! I do a lot of trail riding as well and obvisiously it's worst there. I have a the bike running good with jets now, and have install a boyesen supercooler and a catch bottle, but the bike loves to overheat quickly. I am wondering if anyone has installed a cooling fan on the yz450f and if this helps? I run engine ice coolant and water wetter as well to try and run couple degrees cooler, but this doesn't help. I put on a 2.0 radiator cap and it still pukes out. Thing is the bike doesn't cool down much when riding to suck the collant back in from the catch bottle. Any ideas or tips would be helpful.. Thanks

  • Krannie McKranface

Posted March 17, 2012 - 03:34 PM

#2

It sounds like your water pump is not working, or you are burning coolant through a blown head gasket.
Does your exhaust smell sweet?



You should be able to ride the track all day without overheating, unless you stop and let it idle up steep trial hills.

Edited by Krannie, March 17, 2012 - 03:35 PM.


  • William1

Posted March 17, 2012 - 03:41 PM

#3

I'll add... if you try to keep the radiator full to the brim, it will puke some coolant. It does not want any more than just enough to cover the core.
It should be sucking coolant back from the bottle upon full cool down.
You may want to do a pressure test and also check for bubbles to see if the head gasket is leaking like Krannie suggests.
If you bought the bike new and has always done this and you do not expect the radiator to always be full more than over the core, you need to ride faster. You do not have the electrical power available to run a fan. You might be able to source larger radiators but there is no guarantee that will solve your issue. Jetting certainly will not.

  • yamie

Posted March 17, 2012 - 03:50 PM

#4

I ride the bike pretty hard, been riding for almost 10 years so I'm not inexperienced but no means.. I don't think it's the head gasket cause It happened since day one, and last summer I lost the bottom end so I rebuilt the engine with all new gaskets. Still same issue, The bike is just really hard to start when it gets so hot, so I'm trying to keep it a little cooler. Does anyone know where I can get a fan and the best place to tie in it? And it happens with both the stock water pump and aftermarket.. If i take the cover off and kick it over the impeller spins as well, so i think the pump is working

Edited by yamie, March 17, 2012 - 03:54 PM.


  • Krannie McKranface

Posted March 17, 2012 - 04:57 PM

#5

It still should not overheat, ever.
Perhaps it is jetted very lean.
If it is hard to start hot, your intake valves are probably tight.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • William1

Posted March 17, 2012 - 05:11 PM

#6

How do you plan to power the fan? The stator does not have enough power. You'd have to run a constant loss battery setup.
I doubt it is jetting as with a water cooled bike, jetting will only make the engine runa few degrees cooler. Different water pumps at most mote a little more coolant. You really need to run some cooling sytem diagnostics first. Often the issue is a clog/trapped air/bad radiator cap/bad head gasket. Since you've done a rebuild, that takes the head gasket out.

Hard to hot start just tells me the bike is too rich on the pilot/fuel screw. Tight valves make it hard to cold start.

  • buzzfin

Posted March 18, 2012 - 08:09 PM

#7

Does anyone know where I can get a fan and the best place to tie in it?


It requires an aftermarket stator and rectifier, as well. I have one installed on my '09. Had to custom fab a mount for the fan, but overall it wasn't too complicated.

  • YZPaGuy

Posted March 23, 2012 - 05:46 PM

#8

It sounds like there is a problem with your bike even if it was since new. I have the same bike and race harescrambles with it in some tight slow stuff. It does overheat but not very often. I run Honda Coolant. Make sure your coolant has a high boilover point. I also put Cryca plastics on mine with the power flow shrounds and the front fender that has the back of the fender cut out for better airflow. I tried straight water with water wetter but it didn't have a high enough boiling point. The Honda coolant has been great.

  • Schpenxel

Posted March 24, 2012 - 09:42 AM

#9

It sounds like there is a problem with your bike even if it was since new. I have the same bike and race harescrambles with it in some tight slow stuff. It does overheat but not very often. I run Honda Coolant. Make sure your coolant has a high boilover point. I also put Cryca plastics on mine with the power flow shrounds and the front fender that has the back of the fender cut out for better airflow. I tried straight water with water wetter but it didn't have a high enough boiling point. The Honda coolant has been great.


Agreed. Doesn't matter how hard you're riding it--as long as you're moving a decent amount of air over the radiators, it should not overheat.

There aren't a whole lot of things it can be. Either waterpump, radiators clogged somewhere or head gasket are the usual suspects

  • Weapon X

Posted March 24, 2012 - 07:21 PM

#10

My '08 ran warm as well from new but installed engine ice in her and now she cooled down some but I put a factory FX temp sticker on the left rad so I can keep an eye on things.





Related Content

Forums
Photo

Megabomb Fitment by 288yz450


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply
Forums
Photo

Snake pit oct 30th by The Anvil


Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 replies
Wiki
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info


Articles
  • 0 replies
Reviews

Yamaha YZ450F 2017 by Chris.GVS


Yamaha YZ450F 2017
  • - - - - -
  • 0 reviews
Forums
Photo

First Hare scramble tips by dhend8


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