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Petrol In Oil - Ekk

Discussion in 'Technical and Troubleshooting Torque' started by L0Ki, Feb 18, 2008.

  1. Ok. Before you read this give me the best news first folowed by the bad last.

    My bike (that i bought as a project - GPX250 98') had petrol in the oil. When i say had petrol in it. When i drained the oil i filled it into 2 litre cordial bottle and it filled up 2 and abit which is over the 1.9 it should have. I ran it for about 2mins until i discovered this.

    Also the bike wouldnt idle. When i say idle it wouldn't idle at a normal speed. It would hover aorund 3000rpm then after about 5 secs would slowly die and wouldnt be able to keep it running unless i kept giving it little blats of the throttle. Would this have something to do with the oil contamination or is that another can of worms (carb).

    Now this cant be good can it?

    But what are the possible causes of this (the petrol in the oil)?

  2. Sure there was petrol in there?

    Its possible to put too much oil in which would cause it to run very badly. Fill it up with 1.9L, keep warming it up, waiting a minute, checking level, add some, repeat until you get the right level - do it slowly and keep starting it , turning off, then waiting to check the level - otherwise you can fill up too much.

    Then see how it runs?
  3. Purely guessing here but are you sure both cylinders were firing. Thinking if one wasn't sparking that could account for both the poor running and for unburnt fuel leaking past the piston into the oil.
  4. Umm. I should have been more precise.

    The oil came out like as if it was predominantly petrol. It smelt like it, was very runny and black as.

    I got another question. Can fuel from the floats in the carbs creep into the cylinders and slowly seep into the sump. It doesnt seem laking in compression even though i havn't done a compression test (don't have the required tools). Though i did turn the crank from the access hole in the side of the motor and it seemed normal i guess. It wasnt loose, definetly had compression (this was with the plugs out too).
  5. Will check this. I noticed the spark plugs looked very black when i took em out. Luckily i have some new ones that came with it. I can't try anthing yet i have have dropped the oil/petrol(!) out of it waiting for a oil seal for the output shaft. I pick the part up tomorrow morning so i will finally be able to start it up again and troubleshoot.

    It was weird how it would start very easily with very little choke and stay around 3000rpm though after reving it abit ( no more than 5k rpm) will pretty quickly cut out. It just wont idle unless i kept blipping the throttle. Once cut out it wouldnt start again until i left it for about 1min.

    Could all this be caused by too much fluid in the sump?

    Thanks so far!
  6. Certainly possible if the bike has been sitting for a long time with the fuel tap set to "on" and if the carb needles/seats are worn. That could also explain the poor idle.
    Edit: Any fluid or crap in the airbox?
  7. Yes, you can have problems.
    It sounds like at least one needle and seat has stuck open, and your vacuum fuel tap is leaking. Both items need to be serviced immediately. Severe engine damage can result.

    Regards, Andrew.
  8. The ZZR 250 has a vacuum fuel tap and I assume the GPX has too. These taps can sometimes jam open and will cause the cylinders to fill with petrol if there is an issue with the carbs such as a sticking float.
    The idle issue sounds like dirty pilot jets. If the bike has been sitting around for a while you should clean out the carbs. It is easy to mix up the lines to the vacuum fuel tap. If this happens the bike will only run for a short time but will restart after sitting for a minute as the carb bowls refill. A quick way to check this without removing things is to swith the tap to reserve and if the bike runs without stalling you know the two lines going to the fuel tap are on the wrong way.
  9. Did you miss teh bit about two or more litres of fuel in the crankcase???
    A pilot jet has nothing to do with that.

    Regards, Andrew.
  10. Can you elaborate abit on this. How do i service them?

    Does it require any new parts to fix. Cause I'm going to the Kawasaki place tomorrow morning.
  11. How long has the bike been sitting for? and is there any liquid in the airbox? (quite possible to leak back into the airbox and down the engine breather tube...)
  12. Good news! You have caught it before it went bang. Well, it doesn't go bang when you get a hydraulic lock (fuel or oil in the cylinder/head preventing the piston/crankshaft turning over) - it gives more of a ker-clunk. If you were really trying hard you can bend a con rod!

    There is no bad news, just some time and money to be spent.

    The most likely scenario is:

    1) You have a diaphragm fuel tap which only opens when the engine is running. Until the diaphragm gets a small hole in it, and then it doesn't open at all. Instead, petrol flows out through the small hole, via the vacuum line and into the intake manifold.

    From there, because you have a somewhat worn engine, it runs down past the rings and into the crankcase below.

    2) You don't have a diaphragm fuel tap, and someone left the tap on. That doesn't normally matter much on a japanese bike unless you have a rusty tank (even slight surface rust is enough) or it has done a high mileage and the carb float needle and seats are worn so that they no longer seal properly. Or the fuel is dirty anyway.

    Fuel runs into the carb and keeps flowing in until it overflows the bowls. On some carbs there is an overflow pipe which should dump the excess fuel on the floor. (I don't think your carbs will have an overflow.) Otherwise the fuel flows into the cylinders and then into the crankcase as before.

    How to check a diaphragm tap diaphragm

    A diaphragm tap has a metal housing on the side, usually clamped together with 4 screws, which is connected via a rubber tube (vacuum line) to the inlet manifold of one of the carbs. This vacuum line will be on the engine side of the carb. The diaphragm housing will typically be 2 to 3 cm square and about 1 cm thick, and looks like a flat, square pancake screwed together.

    Remove the vacuum line from the carb; if there is fuel running out or dribbling you have a punctured diaphragm. You either need to replace it, if available, or fit another tap. You can temporarily block the hole in the manifold and seal the vacuum line from the tap so the fuel no longer runs straight into the engine.

    Don't confuse this with the fuel line, which will exit the tap on the side and usually go the side or rear of both?/all carbs.

    Idling problem

    You could have blocked pilot jets. That can happen on japanese carbs. The pilot jets operate up to about 1/8 throttle. The mixture screw controls the mixture at and just above idle, via the jets. If they are blocked, the mixture screws will have no effect. I wouldn't try adjusting them at this stage.

    You could, however, have damaged diaphragms in the carbs, since I have more than a sneaking suspicion that you also have diaphragm carburettors! The symptoms you describe fit this to a T (or a D, I guess).

    Diaphragm carbs have a largish, round or rectangular flat pancake-ish sort of top end on them, much larger than the diameter of the body just underneath. The diaphragms control the lifting of the throttle slide. They too can get small holes which stop them working properly. A very temporary "cure" is to use black, engine gasket grade silastic to seal the holes until you can get new diaphragms.

    If you would like some pics to help ID the parts just ask and I will try to post something.

    All the best

    Trevor G
  13. 100% right. Pull the float bowls off the carbies, give it all a good clean with carbie cleaner and reset your float heights.
  14. @ Trevor: Do I need to buy any parts while I'm at the Kawasaki shop today. I'm picking up my oil seal soon so if i need anything I'd rather not have to make two trips or more.

    Could you possibly tell me the parts that i need to get new ones of?


    EDIT: Looks like diaphragms,
  15. I decided to take some pics to make it a little clearer.

    This is the fuel tap with the vacum hose being the smaller one of them right.


    This photo just shows where the vacumm line (i think) goes. (Its the one at the back of the photo in the middle)


    These are the carbs the GPX250's have. IS it the diaphragm type. Looks like it.

  16. You are soooo good!!

    Pics too.

    Spot on in each case with your assessment.

    Did you check the vacuum line for fuel leakage?

    If there is no fuel your next step is to check the diaphragm. This is potentially dangerous!

    With the vacuum line still attached to the tap (doesn't matter what position the tap is in) suck on the line to produce a vacuum, then seal the end of the line against your tongue.

    The vacuum you create should hold indefinitely if the diaphragm is good (unless you have a hole in your tongue - that's another reason I don't go in for body piercing!) ;-)

    If the vacuum consistently drops away over a period of a second or more, you have a hole in one. You can buy diaphragms for Hondas ($54) or a new tap for $120. Not sure about the K.

    Pilot jets

    Remove the carb bowls. What do they look like inside?

    The pilot jet is the smaller one to one side; the main jet is the larger one in the middle. Usually. When you remove the pilot jet you should be able to see through the itsy bitsy hole in the middle. If the bike has been standing (or leaning) for some time the fuel and muck in there can block the jets.

    Try soaking in petrol, or get some carb cleaner. Then try a little compressed air. As a second last resort use a toothbrush to agitate the edge of the blockage. As a last resort use a soft wire bristle brush and attempt to feed a soft bristle into the hole.

    You can use copper wire from an electrical connector - this is softer than the brass used in the jet, and so shouldn't really damage it. Be careful, though; these jets are around .3 to .4 mm in diameter and can be damaged by using harsh methods.

    Poking wire or anything hard inside a jet is a no-no, so don't tell anyone I suggested this. ;-)

    Carb diaphragms

    If the pilot jets were blocked I would leave the diaphragms until after trying the carbs on the bike again.

    First screw the pilot mixture adjusting screws (head is usually flush with the carb body) in until they gently bottom. Then back them out 1.5 turns - this is a good average setting - if everything else is right the bike will run and idle at this point

    If you still have the funny idle action then remove the carb diaphragm, and inspect it for tears.

    Go easy, they are a little fragile.

    Sorry for the delayed post - work was really busy today. ;-)


    Trevor G
  17. No I did not. As I said a jamed fuel tap COULD cause an issue with the cylinders filling with fuel. Or should I have elaborated on that and said cylinders fill with fuel and in turn run down past the rings into the crank case? Go back and read the OP and you will note that there is also an idle issue with the bike which could be caused by blocked pilot jets.
  18. Yea there was no fuel in the line.

    Will do tomorrow.

    They had a brownish substance on them that was like a film. Wasn't very thick. Just sprayed it with some WD40 and it came right off.

    This is the one thing i didn't look at before cleaning :( (or can't remember if i did), but i got some very thin wire (bit late about the wire warning) through it and then rinsed with carb cleaner/compressor.

    Never! I just had to look at these thnigs. To my surprise they were fine. No visible cracks or tears, just abot of crud lying on the top of them (kinda like a thick grease). I took the whole slide out and the main needle fell out along with a platic thingo. :shock: So i had to open the other to check which way it went. Figured it out aswell as double checking the Ninja Wiki.

    I heard 2.5 turns was the goos starting point. This is what it said on the Ninja Wiki. So i left it at that. Considering i checked how far out they were before unscrewing them and to my surprise they were at about 3.5 and abit turns.

    So maybe this could have been a problem?

    No worries. Thank You Trevor and everyone else who had helped so far. :grin:

    Another quick question again. If the fuel tap is on ON or RES should fuel run out of the tap still? or does the engine have to be running to create a vacuum?

    BTW i went to Team Moto Kawasaki today and he inspired me to pull the carbs down and the whole fuel system startign at the tank he said. But I've gone in reverse. Still have to rinse the tank out to see if had any crud in it.
  19. Go work on some acutal engines and stop talking shit. A flooding carb will cause ALL teh symptoms posted, including a really bad idle.
    If you are going to address one particular fault at a time, and not look at every fault to come to a conclusion, you're wasting your, and everyone else's time.

    Regards, Andrew.
  20. I sometimes find oil in my petrol :LOL: