Fuel in crankcase

[Daisy]

So I had this problem last week where the fuel is leaking through the engine. I've had the carbs off, stripped down and cleaned. There didn't appear to be any sign of wear on the float needles and the levels are as per the manual. It was fine when I put it together last Tuesday and I've ridden it 3 or 4 times since, but today when I hit the start button it wouldn't turn over. I tipped it from side to side whilst looking in the sight glass and the oil* slopped a bit too easily
I put it in gear and rocked it a bit, which allowed it to start. I took it for a run and then left it idling with the fuel turned off. How long should it go before it runs out of fuel? There is no fuel coming out of the tap at the OFF position - with the hose off. I've not been in the habit of turning off the fuel when parking the bike. but it has only now become a problem.
As far as I can tell, it can only be going through the carbs - which means past the float needles - so would I be right in thinking I need to recheck them, or have I missed something?

* At least this time the level is still between the marks, so I know there isn't 2.5L of petrol in it.

[timmyrocks]

were your floats in good condition, if they get a hole in them they will sink and keep bringin fuel into the float bowl and into the engine,
does it run fine when your moving?
id get into the habit of turning the fuel tap off between rides, although before start up leave tap ON for a bit so fuel does fill the bowls.
the bike will idle for a while before running out of fuel with the tap off, id say around 5 mins or so.

did you check your float needle seats?
cheers Tim

[Daisy]

It runs fine when it is going. The floats are fine and the needle seats appeared fine.
I'd like to get into the habit of turning the fuel off, but the tap on the 600 is a piss poor design. It is difficult, for me, to get hold of and hard to turn. So hard in fact, that I can't switch it to reserve on the move.

[mike-s]

take the carbs off, take float bowl off, push the float up on the metal bit that seals the needle on the seat, put water or petrol down the fuel line, does she leak? now do it to the other carbie(s). If this doesn't reveal a leak my bet would have been on incorrect adjustment, now have you taken the floatbowls off and measured how far they are off the flat edge of the float bowl surface? if so, is it in spec?

These are all fun exercises i had to do once or more, not jealous, good luck

[Daisy]

have you taken the floatbowls off and measured how far they are off the flat edge of the float bowl surface? if so, is it in spec?

Yes and yes.
Maybe I should try the leakdown test with more pressure? They don't leak at atmo pressure, but maybe when the tank is hot and pressurised?

/ clutching at straws.

[mike-s]

wait a minute, have you checked the ... ah shit, im out of ideas too.

Does your float drain go off to a tube? or does it just leak down past the screw threads? if the former (likely, as its a newish bike) you can use that along with some clear small diameter tubing (fishtank pvc tubing works well, as long as it doesn't go back in the tank afterwards) to check the fuel height, you may find that the fuel level is going too high despite the floats being correctly set (i.e. a hole in 1 or more floats as otherwise suggested).

[mike-s]

Maybe I should try the leakdown test with more pressure? They don't leak at atmo pressure, but maybe when the tank is hot and pressurised?

perhaps, though it's a flip of the coin if its a factor or not.

[Rusty]

A quick and easy fix would be an electric shut off solenoid, but that doesn't address the problem.

Grit on the needles can sometimes do this. The needles or seats MAY need replacing if the floats are good and the carbs are CLEAN - they don't last forever, unfortunately. The tap's problem is that it hasn't been used.

[deafwish]

Hang on & back this thread up a bit...

Why do you think there's fuel in the sump?
Was it because it sloshed easily?
The easiest & cheapest way to find this out for sure would be to drop the oil out if the sump & get a $50 oil analysis done to determine the level of fuel in your oil.
If there is indeed excess fuel in it, then by all means start stripping bits off!

Daz.

[Daisy]

Hang on & back this thread up a bit...

Why do you think there's fuel in the sump?

Because last week it had 2.5 litres extra in the sump. It was fuel. This time when I filled it with oil I noted the level - and it has gone up. I also took off the oil filler cap. It stinks of petrol - not the expensive oil I filled it with.
AND the oil is too thin, which is why it slops up and down the sight glass like water.

Rusty, the tap does get used. When I switch it to reserve, which isn't often - and every time I take the tank off it, which is getting to be too often. But I am getting quicker at stripping it down.

[Rusty]

Daisy, I'm not saying you don't use it now. Was it stiff when you got it? If so, it's a sign that the previous owner didn't use it much (if at all). If it's stiffened up since, what have you done to it?

My ZZR tap's fine - twists very easily, gets plenty of use.

[Daisy]

The tap has always been tight. I have broken my nails on it several times.

I have noticed though - now that you mention it - that things do tend to stiffen up when these nails get near them.

[robracer]

things do tend to stiffen up when these nails get near them.

[Rusty]

Of course, the other thing that makes 'em stiff is the rubber going hard from plain old age.

[MickLC]

Have you checked the fuel tap to see if the vacuum diaphragm has a hole in it?