Oil in the fuel tank?!

[ProXimaCore]

OK my GF has a Cagiva Mito 125 and I am in the process of getting it up and running just now. Everything done, except change over the old fuel from the tank.

After I emptied it all out into a bucket. I noticed what appeared to be something liquidy, dark red and cloudy at the bottom of the petrol. Taking up about 1/10th of the volume of the bucket. I'm assuming this must be 2-stroke oil right? Should this be getting into the tank?
____________________
Honda NSR125R -> Suzuki GSXR400R GK76a -> Kawasaki ZX636 B1H -> Honda CBR400RR NC29 -> Nothing

[cestrian]

It shouldn't be oil. 2T oil is in a seperate tank and is regulated via a pump. Only in very old bikes was oil and petrol pre-mixed prior to being poured into the tank.
If the bike is new to her, perhaps the previous owner thought it was a good idea to give the bike a little extra lubrication. Some people think this is a good idea but it isn't. Putting extra 2T oil in the tank only serves to weaken the fuel/air mixture, which of course makes the bike run leaner and so a little hotter.

ETA...There is always the chance that it's Redex. I would expect it to mix with the fuel but perhaps not eh.

[Kickstart]

Hi

My guess would be that it is water.

The Mito uses an oil pump, and 2 stroke oil mixes easily with petrol (it will separate, but likely be will mixed having drained it from a tank shortly before).

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[LuckyDip23]

what bout something like redex or a petrol additive?
____________________
I have misplaced my pants.........
Derbi GPR 125 Nude (sold) ~ Yamaha YZF600R Thundercat (written off) ~ Suzuki GSX-R750 K2 ~ Triumph Speed Triple 1050 ~ Ducati Hyperstrada 821

[Jockey]

Redex sounds about right, definitely not water as it looks just like water lying in the bottom.-Jockey.
____________________
Current bike VFR 400 R NC30, others now gone.

[Kickstart]

Hi

This is what water looks like from the bottom of a petrol tank:-

https://www.alfa-pages.co.uk/TempPicture/GPZFuel.JPG

Taken from Charlottes GPZ500 a few years ago. Clearish bit is petrol, orange stuff at the bottom is water.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Wafer_Thin_Ham]

Perhaps the previous owner converted it to run pre-mix?

The oil tank is still there right??
____________________
My Flickr

[ProXimaCore]

I think what Kickstart says could be right. It's not exactly that colour, but that may be all to do with the container it's stored in.

I've got a feeling that the petrol cap isn't air tight actually. It was slightly leaking fuel when I left it upside down in the garage over night. Whole house stank of petrol because of it! Could explain why there's water in it if it had been outside in the rain a few times.

The tank has been emptied before by myself and I know that only petrol has been put into the tank since then, so I can rule out any of the other suggestions.

Thanks for all the suggestions so far guys.

EDIT: I'll take a pic tonight and let me know what you think.
____________________
Honda NSR125R -> Suzuki GSXR400R GK76a -> Kawasaki ZX636 B1H -> Honda CBR400RR NC29 -> Nothing

[ProXimaCore]

On a seperate point. Is there anything I should do to give the inside of the tank a good clean while I have it off the bike and empty?
____________________
Honda NSR125R -> Suzuki GSXR400R GK76a -> Kawasaki ZX636 B1H -> Honda CBR400RR NC29 -> Nothing

[Kickstart]

[The Artist]

Petrol tanks on bikes are not designed for use upside down. They have a vent so that when petrol is taken from the tank, it does not create a vacuum then implode.

Its like when you pour water from a bottle, turn it upside down quickly and water doesnt come out smoothly, it bubbles and splashes everywhere. Air is forced into the bottle and the only way in is through the hole where the water is coming out. Petrol tank is like that but over a longer time and the cap is like making a hole at the base of the bottle which allows air in the top.

sorry about the long winded explanation!