Help with missing oil

[EvanM]

So I am trying to track where my oil consumption is coming from, and have narrowed it down to a possible air box issue. The engine has passed a compression test and leak down test with flying colours. I can see oil in the air box, but am having a hard time figuring out how it is getting there. As of last summer, I was going through 2 litres over 7000 Km.
Anyone have any ideas???
Thanks for any help!

Evan 

[guzzisteve]

Crankcase breathing puts oil in airbox. Overfilled sump or a motor that likes it half way down the stick. Should drain out the hose under bike w/cap on hose.

[ken farr]

I have found that when I change oil, if I refill with 3 liters, including filter, I don't lose/consume any oil.

Same bike.


kjf

[EvanM]

I usually only put the oil half way up the dip stick, measured with the cap unscrewed.
It will consume oil until it is well off of the dip stick

[HardAspie]

I have never owned a Goose. Do they have a "puke tube" as part of the crankcase breather system as do many Honda motorcycles? If so, the tube may be filled.

[Kev m]

I usually only put the oil half way up the dip stick, measured with the cap unscrewed.
It will consume oil until it is well off of the dip stick

Then I suspect something is restricting part of the breather system increasing pressures. At least that's my first thought.

[canuck750]

Hi Evan, that is a lot of oil consumption. On a similar note Kawasaki KLR 650's from 2008 to 2011 and perhaps newer had a bad run of pistons that cause significant oil consumption. Th only cure is to replace the cylinder and piston. I have a couple KLRs and my 2008 is one of the oil burners. Compression is good, bike runs just fine but it will burn a liter every 1500 Km. There is no risk of damage to the motor so long as I keep the oil topped up and oil is cheap! As far as I know oil can only get past the rings or the guides. Guides usually go before rings. May be time to pull the heads and take a look. Cycle Works in town is your best bet for guide replacement.

Hope you can find the cause.

[HardAspie]

How complex is the breather system? Any valves or secondary tubes or such?

[fotoguzzi]

I usually only put the oil half way up the dip stick, measured with the cap unscrewed.
It will consume oil until it is well off of the dip stick

is that what the owners manual says to do? I always checked my Guzzi's screwing it in and back out and then keep the level half way between the marks.
and if you have it over full it will go out the breather..

[guzzisteve]

You can bypass the airbox w/breather sys, run hose in catch bottle, then you ca monitor what it's spewing out.

Been cap on top of fill not screwed in since 05, all CARC, Vintage, etc Smallblocks too


I would pull fuel tank and look for a pinched hose going to the collector tank in front of the airbox.

[fotoguzzi]

Been cap on top of fill not screwed in since 05, all CARC, Vintage, etc Smallblocks too

 

thx, 05 was about when Guzzi stopped making bikes I wanted..

[Trogladyte]

Not familiar with the details of the model. But I'm guessing this is caused by the ball bearing one way valve in the crank case breather. They get filthy, and stick open, allowing oil to pass unimpeded into the airbox. If you don't have oil or compression leaking, I'd put money on this. I'd fit a new one if you can get the part easily. Otherwise take it out and clean it thoroughly with paraffin (kerosene). 

[Dean Rose]

I have found that when I change oil, if I refill with 3 liters, including filter, I don't lose/consume any oil.

Same bike.

kjf

 :1:

Dean

[EvanM]

Hi Evan, that is a lot of oil consumption. On a similar note Kawasaki KLR 650's from 2008 to 2011 and perhaps newer had a bad run of pistons that cause significant oil consumption. Th only cure is to replace the cylinder and piston. I have a couple KLRs and my 2008 is one of the oil burners. Compression is good, bike runs just fine but it will burn a liter every 1500 Km. There is no risk of damage to the motor so long as I keep the oil topped up and oil is cheap! As far as I know oil can only get past the rings or the guides. Guides usually go before rings. May be time to pull the heads and take a look. Cycle Works in town is your best bet for guide replacement.

Hope you can find the cause.

I have pulled the heads and cylinders last winter. I checked the bores, and replaced the rings, and had the guides and valves checked. The spark plugs also have no build ups on them.

You can bypass the airbox w/breather sys, run hose in catch bottle, then you ca monitor what it's spewing out.

Been cap on top of fill not screwed in since 05, all CARC, Vintage, etc Smallblocks too


I would pull fuel tank and look for a pinched hose going to the collector tank in front of the airbox.

I may try this, however, the air filter is completely void of any oil contamination. It is the stock air filter. Is there any other way for oil to get into the air box without going through the filter?
The tank is off, and I cannot see any pinched lines.


Sorry I missed putting the model in (duh me) Breva 1100

[guzzisteve]

Should be a line that goes from the catch tank in front of airbox to airbox body, possibly underneath.

[EvanM]

OK, I'll try and attach a bottle to it once the streets are good enough to drive and see what happens.
Any other ideas?

[Don G]

Have you pulled the throttlebodys off and checked the intake valves for evidence of engine oil, if it was leaking down the guides it would be quite evident by the amount that you are consuming. Just a thought. DonG

[EvanM]

Have you pulled the throttlebodys off and checked the intake valves for evidence of engine oil, if it was leaking down the guides it would be quite evident by the amount that you are consuming. Just a thought. DonG

Hey Don,  I had the top end apart last winter in an attempt to fix this last year. The valves and guides were in good order. I also just did a leak down test,  and the engine is tight.

[Don G]

Evan: But did you check to see if there is now any oil residue on the back side of the valves? Just because someone thought they looked ok dont mean nothing, easy check to do, just cuz. DonG

[Chuck in Indiana]

Hey Don,  I had the top end apart last winter in an attempt to fix this last year. The valves and guides were in good order. I also just did a leak down test,  and the engine is tight.

Really strange. Of course, a leak down test won't show loose valve guides, but if you had the top end apart you'd have found that. <scratching head> *something* is pressurizing the crankcase..I would think.

[Don G]

Ring seal issue? If the leak down passed I would not think so, how long was the test performed? sometimes it is best to leave it under pressure for 15-20 minutes, because if it is pumping the oil up the cylinders, the cylinders have an oil seal, leaving it pressured longer may let the compressed air finally work its way through the seal and finally show the results of poor ring seal. Are the rings directional on these engines(taper faced), perhaps the rings are not installed correctly? Or it needs a realy good old fashioned flogging under heavy load to seat the rings?  DonG

[MGrego]

I have found that when I change oil, if I refill with 3 liters, including filter, I don't lose/consume any oil.

Same bike.


kjf

 :1: :1:  -- This is also the case with my '12 Norge