So went out to start the bike and it wouldn't start. Long story short after a lot of turning over and I mean a lot, (think I need new plugs) it started. Was idling for about 10sec than gave it a few revs and a fair bit (at a guess 50 - 100mL) of oil shot out the breather. What would be the cause of this? I then couldn't get the bike started again but as I said I think I need new plugs as these have been hit with a wire brush to clean them up more times that I can count and the spark seemed a little weak.
Do you mean the crankcase breather? I'm not familiar with the GSX. Oil is overfilled or compression gasses are getting into the crankcase and forcing oil out
Hmm... this could be simple or complex. Seriously doubt its anything to do with plugs.... hmmm. What about: 1. Too much oil in bike 2. Leaky fuel tap (assuming a vacuum petcock) causing fuel to mix with oil and increasing fluid levels in crankcase 3. Needle valve not seating properly in carby causing fuel to leak into sump 4. Ventilation hose not routed correctly and/or blocked? 5. Very bad sceanario - blowby. Lost ring compression/bore trouble - check compression. Good luck, let us know what you find.
So checked compression and both cylinders sitting at just over 150psi. This is what they were when I tested a couple of weeks ago when the bike was ruining fine. Only thing was it was done cold this time but cant see that making a huge difference. Might drain the oil and check amount as the next step. Only reason I mentioned the plugs was that as the bike was not starting thought that excessive turning over with out firing might have something to do with its. My gut feeling is that I'm dealing with two separate issues here. 1st Over fill of oil. 2nd poor spark not enabling firing. Just seemed to occur at the same time. Open to any other suggestions
id check the oil level in case its overfilled - having too much oil can result in much bigger problems as it'll spill over and the crankshaft will whip it into a foam and force it to find a way out of the engine, which never ends well
So I think @joker nailed it with no. 2 and or 3. Dumped the oil and first thing I noticed was was the low viscosity and the other thing I noticed was the unmistakable smell of petrol So there have been a couple of times lately where I have left the tap on "prime" as the vacuum doesn't work. I have noticed fuel that has leaked out of the carbs but didn't even give it a thought that it would be leaking into the motor. Drained out almost 4L of oil/fuel when sump is only meant to hold 2.6L What damage could have I done?
It depends how long it ran with petrol in the oil. The important thing now is to fix your carbies. New float needles and bowl gaskets at a minimum I'd say
First fix that damn fuel tap (I know how annoying they are!) as you shouldn't be running it on prime. Get a new one then reevaluate before digging into the carby too deeply. Solve one thing at a time, if you know the tap is dodgey fix that first. Inside the carby it has probably overflowed the bowls which causes it to leak down into the cylinder (as you've had it on prime). It may not be a seating issue but Linkin is right that area would be the next thing to check. You may need new needles or just some new o-rings on the floats (the latter may just suffice depending on what you find). The damage is hard to tell. Fix the fuel tap then put the right amount of oil in and see if she starts. If she does, warm her up and do a compression test. You may just be OK because you didn't run it much. The damage that can be done is that fuel is not a lubricant so as a replacement to oil (or by reducing the viscosity by mixing with it) it will not be lubricating your rings/cylinder/bore properly and you could wear it out and hurt your compression. If the compression test is OK and it starts you're probably OK, side affect may be a bit of blowby. But keep an eye on it because something like that could do some serious damage if you ran the engine with it longer. It would be a similar problem with water/coolant.
So I'm not too worried about the fuel tap or the carby and at this stage will not do anything about them. This is due to the fact the I am currently in the process of sorting out replacement carbys. Looking at Mikuni VM 28. This will sort out the carb issues. I have also been told that I will be right to use the current fuel tap with these carbys on prime. Is this correct? I think I will replace oil give it a quick fire up, fingers crossed it will be all good, compression test and then wait till I sort out the replacement carbs before I run it for any length of time or take it out for a spin.
It kind of depends. If the carburetor is designed for a vacuum fuel line then you will notice that you will need a second "air" hose from the fuel tap connected to the carburetor to make it work. This line is usually connected between the carburetor and cylinder head on cylinder 1. Something like this: If the new carbies are compatible with your bike and do not require the vacuum connection then it MAY be possible you can run it on prime. Note that with my FZR (which does not have a vacuum petcock) it has a fuel pump, so be aware that it may not be as simple as installing the new carbies and off you go. Here is the pic of my old bandit carbies (vacuum fuel tap). Red is fuel, green is vacuum line: I suggest you fix the fuel tap and use the original carbies. Recondition them if you ned to. Trying to convert the carbies over could cause you more pain and hassle than you may think, but that's completely up to you if you want to try.If you know someone who has done it on that particular bike it may be more straightforward than I think it is and I hope whichever path you choose works out
Changing over the carbs to eliminate the air box and run pods. The replacements will NOT be vacuum operated. This is a bit of a project bike for me to learn a few things on so yea it will cost a bit to do but nothing ventured nothing gained. There have also been a few on here that have recommended I change over the Mikuni VM with pods As for finding a cheap Chinese replacement tap, no luck. There doesn't seem to be anything on ebay to suit. All of the cheap taps have 34mm centres for mounting holes and the GSX has 44mm that seem to be not very common at all
Ah, well that explains why you're looking at it. Good luck... there's a lot more to it than simply changing over to Pods you basically have to re-engineer the fuel/air ratio to spec for that engine which is a lot of mucking around. Hope it works out though, as you said good learning experience. It will certainly be easier if you know others who have done it though!
the vms are a good replacement ,but exie and time consuming ,exie as you will need to buy a hand full of jets etc ,if you go that way ask around for what others are using for a rough start for settings as when you buy the carbs you will only get genetic set of brass with them .if you buy new buy from mukuni aust at Townsville and ASK for tom (not the girl.) and he will help walk you through it if you buy the carbs from them and get rid of those vacuum taps..good luck (also don't skimp on the pods ,cheap chiniese ones are rubbish and also a mongel to tune the carbs on any bike )
Thanks for that info @flea i am buying new from a shop here in Adelaide. They seem to be fairly experienced with carbs and they are willing to help me out with jets and the like. They were also the ones to say that the tap would be fine just using it in prime. Just need to remember to turn the dam thing off
So good news!!! Put in fresh oil and it fired up right away. Think I might just let the old girl sit here in the shed till I get the new carbs to play around with. I'm fairly confident that it was due to leaving the tap on but not 100% sure that the carbies army the issue. Massive thanks to all who helped me out on this one. Such a great community here
