gas in the oil

I just got my 73 commando roadworthy again after a year. Brand new oil and filter. Two days later I noticed the back tire slipping a bit and looked down to see it covered in oil. I limped it home to find the oil tank filled to the top - watery and smelled like gas.

I'm assuming, since I left the petcock on awhile that the gas leaked past the carb and into the motor. with the pecock OFF it had a very slow drip - about one drip every 30 seconds - 28 oz in a day and half. But the carb should still stop it.
I just put on this old carb because I was having trouble with the current carb. But this old carb seems to have gas leaking out of the overflow - that's why I believe it's a bad float situation. I swapped the petcock and carb.

is there anything I need to do to clean the gas out of the motor - or should I drain it and put on a new filter and new oil?

Once gas leak fixed just drain for new oil as heat of running should cook off any gasoline dilution remainders.

Could depend on dilution level . long story .

Napier Sabres were primed with petrol to dilute the oil , to start. But they had 24 cylinders .

Id at least remove plugs and throw an ounce or more of oil in Ea Cyl , to see rings arnt washed out.
dont put the plugs in till its cleared though. Suck out with neoprene tube (of car window washer?)
before fitting plugs, or most of it. Needs a bit with canted engine.

IF its severly diluted , remove sump . Sounds like the bikes just come of lay up , so ' a flush ' cant harm.

Clean oil tank . Fill and leave standing to prime pump , Kick through to clear / prime crank .Then reinstall sump.
Start with the overflow to a container till clear new oils feeding out.How I always change it anyway.

Probly? not that dramatic , but a service under warranty would require it .

a MIKUNI ! :x

The whizz bang was a nightmare (T250 Suzuki) and they say pommy stuffs unreliable ! :shock:
The Pre Unit Bonnie threw any jap part in a day or two, includeing tail light lenses .Record for longivity was two weeks . Despite
tightening every other day. Finally got a real one . No problem then . :lol:
So a certain person has a certain aversion to certain components.

Mk II Amals , 32s , can give 70 mpg , :idea: and Italian stuff ? 32 Dellorotto pumpers for round town
or a 40 or 45 Weber or Dellorotto DHLA are more intrinsacly suited.
Couldnt get mikuni Jet range in N.Z. so wasnt impressed with people melting pistons.

Webers jet easy , and they throw 40 Dels on most 32 things so not unobtainium.

rgla, Yes you have a sticky float or a worn Needle and Seat.
I would most definately flush the engine with new oil. Even if it's a cheaper brand.
Then fit a new filter and the good oil.
It worries me to here of this problem as I too have a drippy tap. Only it is too tight to undo, ( fibreglass tank )
AC.
Mat.. did you know many Euro bikes left the factory with Mikuni carbs in the late 90s. Ducati, Motto Guzzi.
Are you coming over to pick up thos Mk 2s or what.
hehehe.

Long story.

Pressure washed inside of new car engine out yeterday so could be in this week.

Robbed with menace for second time by railway police.
Stubbed out smoke stepping ont train .
Last time Id walked out from under the roof to smoke.
Retards sold off machinery at ADI lithgow so they cant make motorcycles there.
We Call This Progress.


ANYWAY , do they have needle thingos in the dunnies there to, or is it safe ??

Adelaide... City of Churches... drunks, druggies, mafia, triads, petaphiles, footy fans.
Perfectly safe.

Anytime you get gas in your oil, you BETTER dump the whole load.

Gas-cut oil is NOT a lubricant. You are risking spinning rod bearings and cam bushings, promoting quick cam & follower decay, excessive piston & cylinder wear, valve & guide wear, etc.

Dump it and start over. AFTER you fix the petcock and/or float needle issues.

Please fix the petcock drip and float valve leak first. That's asking for a fire and we don't want that. BAP petcocks are only $35/pair and the needle seats can be polished if new needles don't fix it. You're undoubtedly not getting the correct fuel/air ratio too.

Dave
69S

thanks for the replies.
i already swapped the carb and the petcock. And drained the oil from the bike
cleaned the sludge out of the oil tank.
drained the sump and cleaned the mesh filters.

HOWEVER< does this mean that gas also leaked into my primary chain oil?????
No one has mentioned changing this oil because it might be contaminated with gas.
it's a pain because I finally got the the thing to stop leaking but should i drain and replace the primary oil too?

rgla said:

thanks for the replies.
i already swapped the carb and the petcock. And drained the oil from the bike
cleaned the sludge out of the oil tank.
drained the sump and cleaned the mesh filters.

HOWEVER< does this mean that gas also leaked into my primary chain oil?????
No one has mentioned changing this oil because it might be contaminated with gas.
it's a pain because I finally got the the thing to stop leaking but should i drain and replace the primary oil too?

Click to expand...

If you remove the level screw on the primary and you get fluid flowing out then crank oil is getting into the primary. If you only get a dribble and the dribble seems good to the touch and smell then you are probably good to go there.
If you have been able to go through the proper process of getting the primary to seal, then it's probably going to seal again and again.

I guess for engine oil to have got to the chain case, it would at least had to have filled the crankcase up to bearing level
then seeped through. How much mixture came out of the sump.? Enough to do that.
Remove the oil level plug in the Chain case, that will answer your question.
Good luck.

Had the same problem... a few others on the forum have too.

petcock-open-drained-gas-tank-t9504-15.html

Sometimes the needle won't seat because of a piece of gunk. But you may need to polish the needle seat in the bowl. In my case the seat had a visible imperfection when viewed with a magnifying glass.

Best thing to do is pull the bowl. Get a wooden dowel and put it in a pencil sharpener to make a nice sharp tip. Coat the tip in valve grinding paste or other polishing compound. Put it in a handheld drill chuck and use it to polish the needle seat.

For total peace of mind, you can setup a contraption with the bowls out of the bike to ensure the needle is fully seating and no longer allowing any dribble to get through.

I would definitely get those petcocks fixed as well. $35 for a new petcock is a good safety feature. On both my new petcocks the rubber swelled pretty quickly, constricting gasoline flow (would cutout under full power). Running a drill bit through the passage by hand cleared them out... they've been fine since.

Cheers,

- HJ

I left my fuel tap on not to long ago. Completely filled the engine and primary with fuel in two days. Drained everything and put an ounce or two of ATF in each cylinder. Slowly kicked it over a few times and let it set. Smoked like crazy when I fired it up. Heard that ATF cleans carbon deposits, so opted to use it to lube cylinder walls instead of oil. I replaced the taps, but have yet to dig into the Carbs.