Blown Head Gasket? 6th gen

I agree, but it is still not something I want happening right?

 

When the head gasket on my VF750F blew, the motorcycle looked like a crop duster! Even at idle the thing belched copious white smoke. Astonishing, really.

 

INitially this is how my bike behaved but that ceased after I changed the oil and now it just burns oil :/

 

Fantastic, did you ever get a resolution on your problem?

 

Well I ruled out a headgasket failure but at this point I cannot be sure if it is rings or valve stem seals.

 

I figured out where the water came from the first time: somehow rain water is entering the oil system when it rains, bike has to be running to bring water in too. Ideas?

 

Do you park it outside or is this water getting in when it rains and you ride?

 

Only when I am riding it in the rain.

 

Hm, if you had a stuck ring, you would get oil regardless of VTEC engagement. If it happens only with VTEC, intake stem seal might be bad.

Water entering oil is kinda messed up I have to say ... never heard of it, but if I had to guess, front oil cooler or lines associated with that might be the culprit. It is a low pressure oil feed, just for cooling, so pressure might not be enough to show or burst open, but water can be pushed in by the air running over the fins .... I guess this would require taking oil cooler and lines apart and pressure testing it

 

It just seems like something drastically would have to be amiss for rain to get into oil. What about the clutch cover. Perhaps someone went in there and didn't tighten down the bolts, use sealant where they should (around the CKP sensor).

 

Here is the deal, a crankcase is generally under pressure from piston ring blow by. I am with signal in thinking that you have a cover that in not secure. All it would take is for water to collect in a craves and trickle into the engine. It wouldn't take much water to show up in the oil.

 

The only reason I don't think there is any leaks is because water doesn't get in when it just sits in the rain, only when I ride it in the rain.

There is a spot on the oil cooler with oil buildup, I had been wondering about it for a while but it never got any bigger or moved. Will clean it off and see what happens.

If that doesn't turn out to be the problem I will replace all the stem seals for this and other reasons.

 

I just took a look at my 2003 VFR800. It appears there is a "drain" (that's what it looks like) directly on top of the CKP sensor. All I can say its like a channel with a hole in it, that looks like it has some purpose. The CKP sensor area would likely be a weak spot in that seal if it had ever been removed and reinstalled improperly (gasket, sealant). Just a guess. My CKP area has a bunch of rubbery sealant you can clearly see. Its also possible this isn't a drain at all just some strange feature they made, anyone know?

 

CKP?

Also thought I would give an update, I managed to get the compression back to 180 in all 4 pistons using generous amounts of MMO and I have stopped engine braking and my oil consumption is way down. I can still engine brake but if I completely close the throttle as soon as I give it gas it puts out a big cloud. Either valve stem seals or oil control rings but I am leaning towards valve stem seals..

 

I think that's too much oil to pull past even the most worn valve guides. It sounds like it could be a crankcase breather issue.

 

How do I check the state of the breather system? The service manual either doesn't have it or I can't find it.

 

There is probably not a reference to the breather system per say. There are components to the breather system like the PCV valve that will be addressed. The best thing to do is figure out how they are venting crank case gasses and where, then trace the system and look for blockages. The gasses are going to end up in the air box where they will be passed through the intake tract and burned (in the bad old days crank case gasses were vented to the atmosphere.) The idea behind modern crank case venting is to expel unwanted blow by gasses and to create an area of lower pressure inside the crank case. This is accomplished with some form of check valve that allows gasses to escape but closes in the event of negative pressure. If this system gets stopped up bad things will happen from burning oil to massive oil leaks.

 

Actually there is no reference of any sort besides one page that shows the "breather plate" on the underside of the rear valve cover. I am going to take that cover off just to see what exactly is under that plate and if it needs cleaning but other than that I have no idea where to find any of the Positive Crankcase Ventilation system components.

 

After many attempts at fixing it, there appears to be no saving it. Oil continues to burn, plugs continue to foul and the idle is still rough and unsteady. Just going to swap the motor with a used one off ebay and then bore out and fix the old one in my spare time :/