Jump to content

Yamaha Yz 85 problems


Recommended Posts

Hi everyone. This is my first time posting here, and I have a problem I would like some opinions on. My buddy has an '04 yz 85 that had a bad head gasket so anti freeze leaked inside the motor. I was wondering what the best way to flush the motor out was? Thanks

Link to comment
Share on other sites

Replace the waterpump shaft seal, and shaft as well if it is scored.

Head gasket has nothing to do with coolant in the oil on that bike.

drain the trans overnight and refill

What do you mean? Antifreeze in the trans oil would require a new waterpump seal but him saying a bad head gasket is very plausible. Bad gasket, coolant is able to enter from the water jacket into the cylinder on the down stroke of the piston. As for flushing it, if it is a head gasket then once you replace the head gasket simply running the bike should burn out any residual coolant.

Link to comment
Share on other sites

What do you mean? Antifreeze in the trans oil would require a new waterpump seal but him saying a bad head gasket is very plausible. Bad gasket, coolant is able to enter from the water jacket into the cylinder on the down stroke of the piston. As for flushing it, if it is a head gasket then once you replace the head gasket simply running the bike should burn out any residual coolant.

On 2 strokes the engine doesn't share oil with the trans, the crankcase is sealed. 

Link to comment
Share on other sites

On 2 strokes the engine doesn't share oil with the trans, the crankcase is sealed.

I am aware of this. Im sorry I really dont see what you are missing here. Just because its a coolant leak doesnt mean it has to be in the trans. Coolant leaks into the cylinder are just as possible as coolant leaks into the trans thru the water pump seal as you said. But if he suspects head gasket then it why cant it be head gasket?
Link to comment
Share on other sites

It seems both of us were partially right. Your head gasket failed and your water pump seal also failed causing coolant to enter the cylinder and the transmission. Replace head gasket and water pump seal and you should be good to go.

Yes that is possible, what I am trying to say is that coolant from a blown head gasket cannot end up in the trans oil on a YZ85. 

I misread the original post, my fault entirely. 

If there is coolant in the trans oil then yes, replace the waterpump seal. 

As for the coolant in the crankcase you should be able to remove most of it with compressed air, whatever is left will get burnt or blown out the exhaust when you get it running again

also check the head for warpage. 

Link to comment
Share on other sites

Yes that is possible, what I am trying to say is that coolant from a blown head gasket cannot end up in the trans oil on a YZ85.

I misread the original post, my fault entirely.

If there is coolant in the trans oil then yes, replace the waterpump seal.

As for the coolant in the crankcase you should be able to remove most of it with compressed air, whatever is left will get burnt or blown out the exhaust when you get it running again

also check the head for warpage.

sorry if there was any confusion
  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

×
×
  • Create New...