Mechanical help please!

Discussion in 'Off-Topic Chat' started by Thirteen Ball, Mar 2, 2006.

  1. Thirteen Ball

    Thirteen Ball Active Member

    Anyone know anything about engines? I really need some help.

    I thought my li'l dearly beloved motorcycle was fixed when I had the oil system overhauled but it's dropping it all over the place now, and the oil it does still have in it looks like vanilla yoghurt, which ain't good. I keep topping it up with good stuff but it's not helping matters. :(

    It's an air-cooled engine so I can't check to see if the coolant's going down (cos there ain't any!) but it's looking like the head gasket's gone to me. I'm FAR from an expert on this so anyone with any knowledge please reply or PM me

    I've gotta get it stopped one way or another cos the oil's starting to hit the back tyre and that's a potential disaster waiting to happen, for obvious reasons! :eek:
  2. BigHorn

    BigHorn Active Member

    The white deposit in the oil is water.
    If the engine is air cooled rather than by a water system, then that water can only be coming in via the 3 routes:-
    is the oil sump itself contaminated (have you been motor crossing through streams etc with the oil cap off).
    what about the the fuel is there water in your petrol tank?
    The only other place is from outside atmosphere.

    If there has been a loss of power then your analysis could be right. If the head gasket (or the gasket between the cylinders and the gearbox are not air tight then moist air can be sucked in and oil blown out.
  3. Thirteen Ball

    Thirteen Ball Active Member

    I do about 120 miles a week, mainly motorways, but always roads. The petrol's always fresh, so it looks like it's water getting in through the gaskets then.

    I've not noticed any significant loss of power, but I don't exactly 'go for it' much, and it's had little oil niggles for a while now, so It may be that it has and I've just not noticed.

    Looks like I'm going to need a lift to practice tonight! And on Areas week as well!!!! Grr rotten luck.

    Thanks for the help mate.
  4. DaveR

    DaveR Active Member

    I had a similar problem with my car recently, caused by it overheating (thanks to a stuck thermostat) and putting a slight warp on the cylinder head, meaning the head gasket wasn't fitting properly. It is disconcerting when the oil comes out looking like magnolia paint, I agree!

    I found I was losing about a gallon of water a week, much of which was being forced into the oil, some of which was being boiled away and squirted out.

    I don't know anything about motor bikes (I don't know much about cars either!) but I would suggest looking at the head gasket - you may need to get it skimmed if you are unlucky - but you might get away with just reseating the head on a new gasket. Strange that this is happening on an air cooled engine though. Good luck!
  5. Bungle

    Bungle Member

    Another possibilty is the crakcase breather is blocked, this vents any moisture in the oil. The pressure build up may mean its blown out around a crank case gasket. I had this happen on an ford escort.
  6. Thirteen Ball

    Thirteen Ball Active Member

    Cheers all. I'm gonna ring the bike shop this lunchtime and see what they suggest.
  7. Mister 4x4

    Mister 4x4 Member

    Hold up there, sport.

    Actually - you mentioned just having the oiling system overhauled. How did you go about doing this? Did you have a shop do it for you? If so, did they replace the oil pump? And how long ago did this take place?

    The reason I ask is because if there's a new oil pump on there, chances are what you're seeing is most definitely NOT water in the crankcase oil. I say that because water in the crankcase oil looks more like a chocolate milkshake. A Vanilla Yogurt look tells me they might've used some Molly or engine assembly grease (possible Lithium grease as well) to 'prime' the oil pump before refiring the engine and that's what's in your oil. Which isn't necessarily a bad thing, although on a motorcycle that recently had its engine oiling system gone through, I would certainly hope the mechanic would've warned you about that, and fixed the offending leak as well - or at least tracked it down for you and explained what it was.

    In order for the oil pump to run properly, it has to be primed. Filling it with oil rarely works because the oil trickles out before the oil pump is completely installed and the engine back together. So they use the molly grease (which is usually a bone-white color, BTW) to 'prime' the pump, so it has something to move besides air, and it stays put during reassembly. The molly grease keeps the suction process going until the oil comes through - because sucking air won't get the oil moving.

    The little bit of moisture that could get into the crankcase oil via condensation or sneaking in through seals would not turn the oil like that... ever - and certainly not within such a short period of time... only a gasket failure between a water jacket and an oil jacket would cause 'chocolate milkshake syndrome' in a hurry like that. And since there's no water cooling system... well - it's not gonna happen like that.

    And petrol in the oil will only thin it out and decrease the lubrication properties - and make the oil smell like petrol. If you have that problem, check the fuel pump (if equipped) to make sure it's not leaking gas into the block (manual fuel pumps usually run off the crank or the cam), or check the intake manifold gaskets to make sure no fuel is seeping past those seals as well. But if the oil doesn't smell like petrol, you won't have that problem.

    I've rebuilt 3 engines now and I own a Jeep... trust me on this. The Molly grease will eventualy dissipate into the oil as the engine runs and puree's it. However, the first opportunity to get rid of it after the break-in period is done is the best way to go for peace of mind.

    Keep us posted.
  8. Bungle

    Bungle Member

    One area where motobikes differ from cars is that they often have wet clutches, which sit in the engine oil. My old GSX550 has one. Thirteen ball hasn't told us what bike he's got but if its got a wet clutch he might see clutch slip if this was happening

    Agreed about too short a time for moisture to take affect. I wonder what happens to the oil if it gets too hot? Has it got an oil cooler, a bit like a small radiator?

    Another possibility is that because of emmision regulations, the crakcase breather is taken into the air intake to burn off fumes, maybe this has been routed incorrectly.

    Often you will find forums for each make or even each model of motorbike, you could try posting your problem there. Try the Ixion mailing list they are usually very helpful.
  9. Thirteen Ball

    Thirteen Ball Active Member

    It's a Yamaha XJ600S, and yeah, it runs a wet clutch. Only ducatis run dry clutches these days. (and they're REALLY heavy.)

    The overhaul, as I rather grandly described it basically comprised running the breather hoses out and clearing or replacing those that were blocked and changing the oil and filter. The oil pump wasn't changed, and due to the wet clutch, putting moly into a bike gearbox isn't a good idea, cos you don't go anywhere! It's too efficient so stops the clutch working completely.

    The bike has got an oil cooler, on the front of the block but nothing seems to be leaking from there. In fact, it's hard to tell where it's coming from cos there's oil on top of the block, underneath it, behind it on top of the crankcase, and pretty well everywhere, although it's mainly coming from the main breather hose. It's not burning any oil in the engine, although it does smoke when first started, but the smoke ain't blue as you'd expect from oil. It's sorta slate-grey.

    The crankcase breather is routed into the air intake on the US models, but not on the european ones as as far as I know. And the V5 says it's a UK bike.

    I've put her off the road for now and am relegated to public transport until I can get her looked at. It's mystifying me. I've not lost any power at all which is a sure sign of a head gasket popping, I'm at a loss to explain how the oil keeps getting contaminated as there's no water jacket (and i've changed it twice) So I think I'll drop it at my local yamaha dealer next week and see what they say.

    Thanks for your help everyone. I'll stick a post on when I know what it is. (That is, if they can work it out!)
  10. julestools

    julestools Active Member

    When I were a lad, my old bike used to leak oil. I used to spend ages replacing gaskets and seals, making sure the crankcase breather and chaincase breather were ok, tensioning primary and final drive chains, tightening nuts and bolts, replacing blown bulbs but it was all part of running a gorgeous, loud, antisocial 1972 Triumph Daytona. Best bike I ever had (but always in bits). I do miss my Triumph


    Jules (had to push it out of the village before I could start it though)
  11. Thirteen Ball

    Thirteen Ball Active Member

    Ok, for those of you who were puzzled by my mechanical nightmare – here is the solution.

    1) As Bungle suggested, the crankcase breather DOES vent into the airbox. Mine’s a 98 model, and the UK ones followed the US in this direction on the 96 and following models. This means that sometimes, when the engine loses a bit of oil up the breather, it finds it’s way into the air filter.

    2) Since it’s been winter and I’ve been riding through loads of rain and spray on the motorways, it’s also been pulling water into the airbox, which then mixes with the oil, causing the emulsifying effect. Hopefully as the weather dries up, this should stop.

    3) The oil and water mix means the resulting emulsion expands as the engine heats up, pushing more oil + water up the crankcase breather and repeating the cycle, gradually making things worse, and making the oil breather vent more of the stuff as it thinks it's over-full.

    So THAT explains why the oil was emulsifying, even without a water-jacket to leak into it. Combine that with the cold weather never allowing the air filter to dry out, and it works out pretty simple.

    New oil, new filters, maybe splice a T-Piece into the crankcase breather pipe with one end vented to the air to help keep the crankcase pressure down – and things should be fine.

    Oh, and I need to stop riding through downpours!!!!

    Thanks to Everyone who offered Help! :clap::clap::clap::clap:
  12. julestools

    julestools Active Member

    The new Triumph Bonneville has a similar problem with too much water getting into the air box. I have never ridden a bike in the rain since the mid eighties (but italian electrics don't like water)


    Last edited: Mar 30, 2006
  13. Thirteen Ball

    Thirteen Ball Active Member

    As far as I knew, Italian electrics didn't like the very mention of water! ;)

    That said, it probably didn't help when just before new year, I failed to notice a puddle of melted snow, over a foot deep, across the whole road! It was pretty dark at the time, and I wound up wearing most of it. Looks like the rest of it ended up in the air filter!

    Hope the weather dries up soon. Commuting on the train is murder on my wallet.

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