Hi all,

got a 97 CBR900. Just bought the bike back from a buddy after it sat for the last 3 years without running.. Soo i decided to fire it up n what not.. Fired it up, seems to run ok. Now after i turned it off i decided to check the oil and do a change cause of how long it was sitting for.

Went ahead with the oil change, and low and behold.. I have coolant in my oil..

So ive checked pretty much everything and cant find a noticeable leak, or where the coolant would be getting into the oil.

Ive checked the coolant (did a flush to check for oil) not a drop in it, looks pristine.

Checked the spark plugs for moisture, they are dry ( so no blown head gasket)

I put fresh oil in, ran it again, and again, it looks like coolant has made its way back into the oil...

Now i let the bike warm up, and no white smoke out the pipe ( yet another sign it would be a head gasket if it was white)

Ive read that it could be a water pump. So i pulled this off, and nothing from the telltale hole or weeper hole.. I even pressurized the cooling system with it out of the engine and didnt notice any fluid...

Now after reading for hours online, ive seen it could be the Oil cooler oring causing the leak.. Anyone heard of this?

Im at the point now that i am going to change the o-ring, but i really dont want to waste another 4L of coolant and oil to to have this not be the issue.

Does anyone at all have a clue what would be causing the leak or had similar issue?? Please help

 

have you checked to see what amount of coolant you're losing? if it's not that much coolant (but you're sure there's coolant in the oil), it might not cause white smoke - but it could still be the head gasket.


i'd replace that water cooler o-ring that you've said you've heard about being the cause... it would suck to waste more oil/more coolant, but it's much easier to replace those things instead of the head gasket...

 

The 900rr doesn't have the cooler oring set up like the f3s, Its external. Look closer at the water pump seal.

 

Yes i did notice that. I did do a pressure test to see if the internal seal would go, but so far no leaks.. Im leaning towards just picking up a jar of the "Pelletized Stop Leak" It says it "Helps to seal internal, external and coolant-to-oil leaks with coolant applications"

Ive also found that whoever took off the oil cooler before put a smaller(not very thick) looking oring on, and used liquid gasket or something. There's alot of gray gunk stuck around the old o-ring

 

When that oil cooler oring leaks, it leaks oil only, on the outside.

I don't recommend using the stop leak stuff. It will cause more problems than it's worth. Fix it the right way, when you figure out what's leaking.

 

I kinda wondered if that was the case.. cause i couldn't fathom how coolant would leak past that o-ring into the oil.. When i did the second oil change, the oil was pretty dirty, but when i poored some of the old oil into a bottle and left it, i didn't notice any separation of coolant or water. It could be cause i didn't poor all of the oil into the bottle, but i figured i would still see something even with the small amount i poored in... I'm wondering if maybe the 2nd oil change was just clearing out more of the crap that was still in the engine.. Im going to put fresh coolant and oil and a new oil filter on today and see what happens.

Just sucks to go through more coolant and oil.. almost getting worth it to tear the engine down and rebuild.

 

If it was the head gasket, wouldnt the spark plugs have some sort of moisture on them?

 

If it was the head gasket, wouldnt the spark plugs have some sort of moisture on them?
Sometimes, but not always. If coolant is leaking into the combustion chamber it might. The engine would have combustion gasses and pressure in the cooling system and probably running a bit rough.

You're dealing with mixing coolant and oil. For the gasket to be bad with those symptoms, it would need to be bad between the coolant jacket and oil return port, or where the cam chain rides.

 

O ok, next question.. put fresh oil and coolant in.. Started it up, cant see any coolant in the oil currently.... but...

Bike runs for a minute, warms up, then decided it wants to stall out.. Unless you keep the revs pretty high, and even then it just want to die and not start up right away.. Carbs not sync'd correctly?

 

my money is on leaking head gasket it would run crap just like your saying it is, wouldnt necessary show on plugs as the heat will keep them dry,when the bike is running watch the expansion bottle you should see air bubbles appear every now and then if gasket is blowing ,if thats ok gasket should be fine , a compression test might be another option .