Looking in to why my XJ drinks oil

[J.M.]

My XJ600 '97 drinks oil currently. I've finally finished my exams and returned to my parents, meaning I am finally able to investigate why.

I've just performed a compression test. Very happy with the results. The Haynes states 157psi, my results were (1 being left, 4 being right):
1: 180psi
2: 170psi
3: 175psi
4: 180psi

Whilst checking compression, I noticed this:
https://i.imgur.com/tDZ7Elp.jpg

That is the rubber between the airbox and the carb overflowing with oil. The photo is of cylinder 1, the other cylinders do not appear to have the issue. However with the bike being on it's side stand, it is entirely possible that the oil is just grouped down to the LHS of the airbox, hence overflowing.

What would cause the airbox to fill with oil?

Finally I have noticed a very small trickle of oil on the stator cover. Not enough to make a noticeable impact on the oil level, but something that should be fixed. It 'looks' to be coming from the base gasket, suggesting that the base gasket needs replacing.

Can anyone offer some thoughts/advice? Cheers!
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2004 R1 & 2018 XSR900

[J.M.]

Oh yes, here is a video of the bike a month or two back. I've commuted only short distances on it since then so I've simply kept the oil level topped up as it didn't feel down on power.

https://www.youtube.com/watch?v=X5BpzRsbQuY

It only burns so visibly when the engine is completely warmed up, like after a hoon. At the end of my 5 mile commute I could smell a little burning oil but there was absolutely no visible exhaust smoke.
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2004 R1 & 2018 XSR900

[Islander]

Worn valve guide(s)?

[garth]

My xj's airbox used to fill up with oil if i was, errm, preserving front tyre life

[P.]

While you are there, check the airbox pipes and the carb heaters...failing that link the oil lines rather than heating the carbs with oil. Eliminate any cracks in that for a start.

[J.M.]

Haven't done any wheelies in ages because I don't want to knacker my head bearings/wheel bearings before Spain!

Will check breathers and stuff. Need to grab myself a new spark plug as somehow I've managed to bend one of the threads for the HT caps

No idea about valve guides and stuff. I'll check the simple stuff first. If that gives me no success (I hope it will) then I can crack the head open and take a look in there. Apparently I can get a full top end gasket set for the bike for £50 so I would be able to replace all the gaskets and seals.
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2004 R1 & 2018 XSR900

[Alpha-9]

Clear your carb breathers/all breather pipes, common xj problem
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Fzr-600 1999

[DrDonnyBrago]

Crankcase breathers normally route to the airbox.


When my CBR went ice skating oil was pumped into the airbox via the breater.

[J.M.]

I checked two breathers. The once from the rocker cover and the one from the crankcase. They both seemed to be clear.

I cracked the air box open. There's definitely a sparing amount of oil residue in there, but no puddles.

Me and my dad just spent ages trying to crack the carbs apart. Got them apart and now I've got them soaking in petrol to allow them to be easily cleaned tomorrow. Putting on new screws on the assembly.

There wasn't really any signs of the carbs being full of oil, although I suppose there wouldn't need to be loads of oil in there just to tint the exhaust smoke.

Once I've finished checking things through and got a replacement spark plug for the one I bent I can take the bike for a run with a container built on to the crankcase breather to see whether it fills up with oil whilst riding. I want to fix the fuel tank petcock before that though; the vacuum switch isn't working fully. Should be a simple fix.
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2004 R1 & 2018 XSR900

[J.M.]

Firstly, how do I remove the rocker cover? My Haynes shows 8 bolts rather than 7 and a nozzle. I think the nozzle needs removing before I can remove the rocker cover but I'm unsure how to remove the nozzle. Any ideas?

https://i.imgur.com/Rul24if.jpg

Also... fuel petcock looked nasty (That's all sorted now):

https://i.imgur.com/6vRHkvB.jpg?1
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2004 R1 & 2018 XSR900

[Alpha-9]

I cleared the vast milky ejaculate from my pipes earlier, it was satisfying.

I couldn't get my rocker off either, too awkward
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Fzr-600 1999

[J.M.]

No milky stuff in my pipes at all, meaning I may well have to possibly tear off the head and replace seals

I got that nozzle off. There's a torx bit hidden inside of the nozzle. Careful though... I wouldn't fancy rounding that off

Waiting on the airbox t-pipe now so I can reassemble and take it for a blast with a catch can installed on the crankcase/valve breathers.
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2004 R1 & 2018 XSR900

[J.M.]

So things I've checked currently:
Crankcase breather pipe: completely clear
Valve cover breather pipe: completely clear but t-pipe on airbox broken so not properly connected
Nozzle on valve cover: completely clear
Carbs: all cleaned out, no signs of oil inside (hinting that the issue may not be oil in the airbox)
Carb heaters: all clear. Blocked the nozzles and tried blowing air in - no air leaks so that means there's also no oil leaks from heaters in to carbs

Also repaired the fuel tank petcock.

So yeah. I'm currently thinking a valve seal or something.
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2004 R1 & 2018 XSR900

[P.]

Valve stem seals, assume you can do these at your house right?

Must see if we can find some issues... my R1 is gonna break soon from some dodgy pipe... I can sense it.

[N cee thirty]

can't you just put the breather in to a bottle and then refill teh oil again when its full, saves adding oil/ burning it.
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'00 Aprilia RS50 > '92 Honda CG > '99 Yamaha Fazer > '91 Yamaha RXS > '79 Suzuki X5 > 01' Honda Cg > 07' Honda Cg > 82' Kawasaki Z200 > suzuki gsxr 400 gk73a > honda vfr 400 NC30 Mod 2 Passed 09/06/2011

Jewlio Iglesias wrote: I actually did vote BNP once

[J.M.]

Yeah can do those easy peasy. The only part that is worrying me is changing the base gasket as I've never taken off a cylinder body before.

Hope your R1 doesn't break... I'll feel like a right nob if it does lol.

Rob, I don't think it's a problem with the breathers. The airbox must just have had some residue oil left in there from wheelies 500 miles ago or so. I've just been researching the side affects of worn valve stem seals and my symptoms seem inline with this. I think my base gasket needs changing anyway, so I may as well do the rebuild and then result to a bottle if that doesn't fix it.
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2004 R1 & 2018 XSR900

[_Iain_]

J.M - if you need dem gaskets, email/text me and i'll order em up at mates rates for you.
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Please be aware that the above post may be full of complete nonsense.
Riding: '07 KTM Duke II, Baotian BT49QT-20 Driving: '88 Volvo 340

[J.M.]

Boss! Thanks!
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2004 R1 & 2018 XSR900