Oil Frothing

**Mark** · #1 22 Jun 2005

Hi all

I have recently noticed that when I check the oil level of my XT600E, having just turned the engine off after a 30 mile ride, there is a lot of froth on top of the oil.

The bike has done 75000 miles without any major engine work (just a cam-chain change and a new set of piston rings 50 000 miles ago), uses about a litre of oil in 1000 miles, so is probobaly quite worn but starts readily.

Any ideas why the oil is frothing, is it a major problem?

Thanks

Mark

**goodwoodweirdo** · #2 22 Jun 2005

Sounds to me you have air in the oil system. I'm guessing if you don't have an oil leak.

Then if you get compression from the cylinder pass the piston rings you'll end up with burning of oil and or pressure in the oil system.

Check the compression
Renew the oil / filter
How old is the oil

Only then would I think about a bore and piston.

**Steve Pickford** · #3 24 Jun 2005

I doubt if it's air in the system. For air to be sucked in & pumped through, you'd have to be low on oil in the first place.

It's possible that a partially blocked oil line or oil way could cause cavitation?

Remember that the oil has a hard time, pumped through various orifices at pressure, compressed & sheared by many components. I'd suggest just changing the oil & filter, paying attention to the oil level & then see what happens.

**Mark** · #4 24 Jun 2005

Thanks for your replies

The froth was noticed before and after an oil change, and I keep the level topped up after a 30 mile run.

I guess that blow by past the piston rings is the cause, but wondered if anyone might say dont ride it any more until it's sorted because ...

Mark

**Matt Cartney** · #5 24 Jun 2005

When you say 'froth' what does it look like? Emulsion from water contamination of oil can sometimes look a bit frothy? That could simply be due to condensation building up over disuse over the winter perhaps.
matt

**goodwoodweirdo** · #6 28 Jun 2005

Just a thought, did you have the air screw open on the oil filter casing, when changing the oil ?? It enables you to bleed the oil system of air....

Good luck

Matt

**JonStobbs** · #7 28 Jun 2005

Practically all wet sump engines will show a little "frothing" on top of the oil after a run,which is quite normal and nothing to panic about.Have you looked at any other XT's to see if yours is any worse than others? Some bikes don't have an inspection glass for the level,but have a dipstick instead and any "frothing" isn't detectable on these.Also,some that do have a glass eye also have a funny steel plate fitted behind the glass to stop the froth from showing.Can't remember if the XT has this.I think as long as the oil level isn't too high and oil consumption isn't too bad i'd not be that concerned about it.(mechanic of some 16 years experience)

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Just going for a short ride on my bike....

**Mark** · #8 28 Jun 2005

Thanks all for your replies.

The froth is just lots of bubbles in the oil when the dip stick is removed from the frame top tube come oil tank. I'm sure it didn't used to do this - maybe I'm riding it harder.

As no one has replies ' Oh my GOD, it's about to explode etc, I'm not going to worry about it.

I've never opened the air blead screw on the oil filter housing, though I sometimes wonder if I should. After an oil change I start the bike with the oil filler cap / dip stick removed and watch the level drop, and add the last 0.2 or 0.3 litre of oil.
I assume that the level wouldn't drop if their was an air lock.

Mark