Overfull of oil?

[John Stenhouse]

I took my Tiger to France recently, loaded in the back of a van, after I arrived, it sat with a full tank on the sidestand and smelt strongly of fuel, there was a small amount of fuel from the overflow pipe on the floor. Took it to Le Mans and filled it up again after a couple of days and then it sat again on the sidestand for two days before I rode it home.

I arrived at the ferry port and put it on the main stand and went for a pee, came back and found it leaking oil from somewhere on top of the engine, the sight glass on the side of the engine was too full so I guess it's got fuel in the oil.

Can someone explain the mechanism, since I thought fuel injection eliminated the possibility of fuel leaking through to the engine?

[metalguru]

The only logical way oil can get contaminated by fuel is if the injectors are hosing or dribbling/leaking, ie not sealing.
Usually the hosing is accompanied by rich or uneven running and a increase in fuel consumption. Have a sniff in the oil filler and see what the oil smells of.

Would not recommend running the engine at all until the problem has been identified as the oil is diluted and WILL NOT lubricate.

The overflow leak could be attributed to the filler cap venting with a full tank. As the tank warms especially in a vehicle, so the fuel will expand and flow through the vent after overcoming the valve. A small amount of fuel will make a very large area.

Just as a nice to know, I have had many bikes in recently with many fuel problems after the Winter lay up and all are guilty of using supermarket cheapo fuel. (In UK). Many engineers are steering riders away from the supermarkets to branded fuel.

Here is a photo from the last rebuild I did on a somewhat rare engine due to cheap fuel. The engine seized solid at 'speed' and luckily the rider stayed on and in control. This was present in all float bowls although the bike had stood for a while. Injection equipped engines are less prone to this problem but a problem never the less for any seals etc which are affected by Ethanol.

[John Stenhouse]

Took it to the dealer I use today, where we drained the oil which didn't smell of fuel so we pulled the tank to have a look about and the drain from the airbox was what caused the leak down the side of the engine, it was split so the oil that was in there came out half way down the pipe onto then round the crankcase.

Million dollar question was why was there oil in the airbox? We think it had been overfilled and the temperature in France was enough after the run to the port to allow the engine breather to get some oil in and up to the airbox.

Any other ideas welcome.

P.S. We've filled it only half way between the marks on the sight glass this time and we'll see.

[Sin_Tiger]

Since you've drained the oil you'll be sure is not water.

Other than smell, the way to check fir fuel dilution (this applies equally to diesels) angle a flat metal plate, not coated preferably,  at about 45° (not critical). Place one drop of good oil and one of the suspect oil at the top at the same time and watch them run down the plate. The good oil will run slowly with a pronounced "bead" near the original size, a contaminated drop will run markedly quicker and broaden out wetting a wider area.  Poor man's viscometer.

[Bixxer Bob]

Oil in the airbox is a sign of the stator oil seal leaking.....

http://www.tigertriple.com/forum/index.php/topic,7689.msg53241.html#msg53241

[John Stenhouse]

UM, does that apply to an 885i? Yes it has a cover but theres no stator inside as it has an external alternator, I wonder if there's a seal there?

[John Stenhouse]

Point taken BB, so had a look on World ot Triumph site at the pics a sure enough there's a seal in there, so ordered that and the gasket and sealing washer, plus finally got an order in for the tank connectors, the males were done on the re call but the females now leak so metal ones ordered.

[Bixxer Bob]

Having read the thread, no doubt you'll realise the seal is a bitch to fit without nipping it?  Or maybe EB is cack-handed....  time will tell

[John Stenhouse]

I'll find out tomorrow, seal came in and collected today, apparently you fit it and bolt it together and then leave it for at least 15minutes. I feel a tea and flapjack will fit nicely in there.

[John Stenhouse]

Ok, I changed the seal, and it has lasted until today. It was fine for the Tiger meet, then one ride out to Ludlow and another down to Warminster,checked the oil last evening before riding home and it's down and the air box drain shows signs of oil having come out.There were some marks on the shaft when I installed the seal, a couple of scratches down the long axis of the shaft, maybe they are causing the seal to leak?

[motoOzarks]

Scratches and grooves will eventually ruin a seal.  Especially an older dry one.

Oil can use the scratches as kind of a ditch or valley to travel thru and transfer oil from one side to another.

Is it building pressure behind it?  pushing oil past the seal?  In other words is there a crankcase vent (dunno if it has one) blocked?

[John Stenhouse]

This is the crankcase breather that's leaking

[Bixxer Bob]

I think I mentioned they were a bitch to do, I think EB had three or four goes at his.....

[John Stenhouse]

Thanks BB, I think the next plan is to get the local Yamaha dealer to have a go