Hi all - new to the forum. I've recently bought a 1995 XT600E for commuting duties through winter, having owned two 350s and a 660R in the past (I just love XTs). Having read a lot on this forum, I am now seriously thinking about prepping it for a bit of serious touring. Just when you think you have your life in order ...

Anyway, a question. I've just done a full service as previous service records were non-existent and the bike is fairly tatty. On opening the air filter box, I found a quantity (about 20ml) of engine oil in the bottom, although the filter element was not contaminated. This has accumulated in the last 1000 miles, as I had a look in there when I bought it, and there was oil in there then, which I cleaned out. I would suspect worn rings, allowing cylinder pressure to blow oil out through the breather, but I'm open to any advice or ideas from someone with a better knowledge of these engines than I have.

Many thanks.

Rich
XT600E 1995

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2006 XT660R daily ride, 1994 XT600E about to be reborn, Blog: http://goingfastgettingnowhere.blogspot.com/

Sorry, should have said it is a 3AJ motor.

(At least, it has "3AJ00" written on the LHS of the cylinder.)

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2006 XT660R daily ride, 1994 XT600E about to be reborn, Blog: http://goingfastgettingnowhere.blogspot.com/

The engine is designed so that the crankcase will breath into the airbox (as you know ofc). Therefore it is only natural that there should be oil collecting there, there is even a little drainage tube with a bung in the bottom to allow you to drain this without opening the airbox. Essentially, unless the amount of oil in the airbox is excessive (contaminateing the airfilter) then don't worry, all is as it should be. 20ml is fine.

By far the most common reason for excessive oil in the airbox is over filling the oil tank at oil change. Check this before worrying about other problems, especially if you have no other symptoms.

Its not usual though, at least in my experience - I've never seen a drop of oil in my airbox in 20 years running.

Lots of 'orrible black stuff, coating all surfaces including my 'didnt stay red for very long' K&N filter, but that seems like 'normal' crankcase breathing?

Thanks guys. I hadn't spotted the drain hole, so I will look for that and see what happens. The oil in there was clean, i.e. used engine oil colour, not black horrible stuff, but the quantity was more than I was expecting to see. Most engines I have worked on are a little dirty in there, but to see a pool of oil in the bottom was a bit of a surprise.

I've been looking back through old posts on the forum, and there was one guy who was getting the same thing and it turned out to be overfilling with oil at a change. I have been checking the oil level as per the manual (run for 10 mins, stop engine, leave for 5 mins, check with dipstick unscrewed and bike vertical) and have kept the level up to the max mark. I check every week and have occasionally topped it up. I wouldn't expect it to be overfilled this way, but now I am not so sure.

And another odd thing ...

The manual gives the quantity of oil for a filter change (no dismantling) as - I think - 2.8 litres. I bought a 4l can of oil and used all of it before the oil came up to the right level as described above. So I have put in way more than recommended (yes, I bled the filter housing) and this is making me wonder what I am doing wrong. Have I got the level-check wrong (which would account for both the issues above)? This was after I noticed the oil in the air filter, by the way, so not connected.

I'm not using the bike this week for other reasons, so I will leave it to the weekend and look again. Perhaps drain the oil and start again.

Thanks for the help.

Rich

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2006 XT660R daily ride, 1994 XT600E about to be reborn, Blog: http://goingfastgettingnowhere.blogspot.com/

Hello and welcome Rich.

it's most probably caused by too much oil in your engine.
I had the same inconvenient on my TTR600 (3AJ).

When I had an MOT done, about an year ago, also got oil / filter changed, by a garage, and they got it wrong... by putting too much oil in.

Not a major problem i think, but the engine gets all dirty by spluttering it out (in the air box too).

In my experience, i noticed that there are not many people around (in the mechanic places) who know exactly how much oil goes in there... apparently it's a bit tricky.
It's far better to do oil / filter change by yourself, as it's easy to get it right, with a bit of patience.

Put the oil in (not too much.. around 3 lt. i'd say)... go for a 10 mins spin... check the oil level again, top it up... go for another spin... check it again, top it up... and keep doing so till you reach just below the top mark (and doesn't go down).
If you go touring... remember to always have some oil for top ups with you (especially in hot weather).

Doing the oil changes by yourself also avoids the danger of the mec ruining the thread on one of the oil filter cover's bolt (top right one, i think), which is a very common problem on these engines.

Lots of guys on this forum will tell you that they would never let a mechanic do the oil change on their XTs, just because of this.

Good luck
diego

Hi Diego

Many thanks for the info. It certainly looks like I have too much oil in there. I've only done about 50 miles since I serviced it, so I will keep it off the road until the weekend, half drain it, and then do what you suggested. If it's blown half a litre into the airbox by that time, I'll know why!

Cheers

Rich

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2006 XT660R daily ride, 1994 XT600E about to be reborn, Blog: http://goingfastgettingnowhere.blogspot.com/

It won't blow half a liter in to the airbox but it will surely drop through a small tube that you should have between the engine and the rubber boot of the rear shock while you're actually riding...

When you stop the bike be sure to set it on a clean place where you can see if there are any gravitational oil drops on the floor close to where I just mentioned.. (they might not drop instantly)..


Have fun!

Vando

Thanks Vando

I can safely say the bike has never dropped any oil since I have had it. It's always parked in the same place, and I am sure my wife would have noticed something and pointed it out - gently and reasonably - if it had.

Like: "What's all that oil doing on my drive, you idiot?"

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2006 XT660R daily ride, 1994 XT600E about to be reborn, Blog: http://goingfastgettingnowhere.blogspot.com/