yz450f overflow problem

[Bigfoot0518]

I put a new top end on my 04 yz450f and it wont stop leaking out the overflow. I tried a new radiator cap (didnt work) checked the oil for water no water. The only think i can figure is i didn't toque the head right and compressed gas is getting in the cooling passages.what do yins think?

[Trailryder42]

After having run the engine and the system cools off and you open the radiator cap, what is the level? Is it still slightly above the core or not?

[Bigfoot0518]

Its below the core after only a short ride.

[Trailryder42]

Is the new radiator cap the same temperature cap as the old cap?

 

And what temperature cap are you running?

 

Did you use new head / cylinder gaskets?

[Bigfoot0518]

The new radiator caps rated higher 1.6 and yeah all new gaskets

[SteveThe Snakes]

First off are you using at least 50/50 to prevent boil over or more antifreeze.

[Bigfoot0518]

Yeah even tried engine ice

Yeah even tried engine ice

[FORMA MOTO]

Yeah even tried engine ice

Yeah even tried engine ice

 

And did you flush out all the water mixture per the engine ice instructions ?  

 

Have you bleed the radiators for air?

[Bigfoot0518]

I flushed out the system when I put the engine ice in how would Ya get any air out of the system and would that really cause that problem

[grayracer513]

Air purges itself, so it's a non-issue.  If the system is filled at the radiator, that's all you need to worry about as relates to that.

 

My question is, how did you torque the the head?

[Bigfoot0518]

Didn't use a torque wrench to torque the head to spec so I figured that was the prob

[motohead13]

Torque to spec, criss-cross pattern

[damnbiker94]

Time for new head gasket and a torque wrench. Hopefully the head wasn't warped by whatever tightening method you used the first time.

[grayracer513]

Yes, and the torque procedure is more complicated than simply running them up to a number, too. 

 

Read: https://www.thumpertalk.com/topic/873863-cylinder-head-tightening/

 

Torque pattern sequence is:

 

1) Left rear

2) Right front

3) Left front

4) Right rear

[Bigfoot0518]

I torqued it to spec runs great now .. Thanks for all yins help