petrol in oil!

[livingdeadhead]

got my new (to me) r65 , checked the oil was shocked to find it was contaminated by petrol , oil+petrol in total was just over 3 litres , have drained it and filled with good oil , going to run it up over the weekend and change the oil and filter again, bike had been stood covered 3 miles in last year, any one tell me how it happened and is it a fault? thanks

[nhmaf]

Possible (likely) that the fuel petcock was not turned off when the bike was put up, or the fuel petcock is leaking.

The float needles in the carbs will not always shut off the flow of petrol into the carbs, due to a bit of grit, piece of rubber fuel hose,e tc. on the seat, hardened rubber, worn tip, and binding float levers.   This can also be exacerbated when the bike is left on the sidestand, not centerstand, for long periods with the fuel petcocks left on.

I would first ensure that your fuel petcock does indeed turn "off" by taking a spare empty fuel container, turning the petcock to the off position, and then removing the hose from the petcock with the container held underneath to catch any fuel.   If you end up draining your fuel tank into the container, it is time to replace or rebuild the petcock.   If the petcock is working properly, it may have been that the petcock was left open and for a period of time, the gas cam into the carbs and the float valve(s) were not able to close it off completely.  Eventually the fuel level rose high enough to enter the intake, drip down on the piston and run past the rings and into the crankcse.

Always make sure that you turn off the fuel petcock on these bikes, whether you are parking it for 4 hours or for a fourtnight..

[wilcom]

Check to see if you have the dual independent float bowls sold by Bing. They are without the overflow tube so if you have a leaky needle and seat the fuel enters the motor rather than leaking on the ground.

When I had those on my R65 I would come out and the cylinder would be locked because of the fuel in there. Sooner or later if I didn't ride it often it would have made it's way passed the rings and into the sump.

Should have read Bum's page on those before Bing talked me into the "latest thing"

[livingdeadhead]

thanks for the info guys, just checked the level and it seems ok, (still smells a bit of petrol tho) , it was probably due to being stood for over 12 months , anyhow , got some miller oil for it and the filters, i'll warm it up and change them tomorrow and let you know how i get on. thanks again! 8-)

[montmil]

If there really is gasoline in the crankcase oil, I would drain it "cold" rather than risk even the slightest chance of bearing damage.

Fresh oil and filter... then a first start.

[smiley=2cents.gif]

[livingdeadhead]

changed oil, wont start! runs on one , swap plug, runs on other side! new plugs monday ! ah happy days.....lol

[livingdeadhead]

new plugs, started , running fine! phew!

[steve hawkins]

I am ashamed to admit that this happend to me when I left my bike in the garage over winter without properly laying it up.  I never meant not to ride it.  Forgot to turn the petcock off.

In the spring I started it up for the first time in months and pootled off down the street, only to find that a petrol/oil mix was being blown out of the engine and was all over my rear wheel, etc.  New oil and filter sorted it.  But I had to look at the trail of oil stain in the road for months and months......And months.  To remind me of my stupidity.

Rev. Light

[georgesgiralt]

Hello !
You are lucky that the petrol found its way to the oil and did not stay in the cylinder.
If there is LIQUID above the piston when you try to start the engine, as liquid is not compressible, you risk ruining pistons and/or piston rods...
Could be expensive.
I saw a Triumph engine which has sucked oil trough the carter ventilation system during an accident. As no one was injured, the owner tried to restart the bike and hear a strange noise. Boys, you should have seen the inside of the engine....

[livingdeadhead]

all seems ok now, changed oil , filter and plugs , was probably due to petrol being left on, now just the new stuck seat to sort!