Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Oil leaking from carb

Wow that seems very excessive Martyn

50 years ago my first motorcycle was a BSA A10 650cc Golden Flash with sidecar and I passed my test on this.

On the bottom of the sump was a small square cover plate held on by 4 short studs with nuts and spring washers.
When this cover was removed it revealed the pick-up pipe that leaded to the scavange side of the oil pump. The end of this pipe was fitted with a small fitting comprising a ball on a seating that was held closed by gravity. BSA called this the "Anti-syphon Valve". If there was even a very small particle of dirt on the seat and the engine was not run for a week or two, and particularly if the oil pump was worn, the oil would drain down from the oil tank (which was higher than the engine) back through the feed side of the pump to the scavange side of the pump and then into the sump.
THis resulted in clouds of blue smoke on start-up but if the bike was used regulaly this did not occur.

"About 1000 miles per gallon is what's claimed, although I will be using a bit more as I keep the oil injected at a slightly higher rate as oil is cheap; rebuilds aren't".

"Wow that seems very excessive Martyn"

Compared to the less than 200 miles to the pint of oil that my Vincent Series C twin used to do, it doesn't seem too bad. Despite it also being dry sump, it used to blow most of the oil out of the timed engine breather that used to open when the pistons were on the way down and close when they were on the way up.

This thread reminds me why I delight in having a Morgan and not a classic bike, or car.

This thread has drifted from the original question All very interesting but can we get back on track?

Tim

Gambalunga is right
I closed the air breather to the admision'
And put it directly under the car with a air filter

Back on the topic:

The oil tank is mounted above the "carb" and the breather from the crankcase goes to the air filter.

IF the oil has drained back from the tank into the sump then it could rise up through the vent into airbox, soak the filter and run out of the carb body.

Why could the oil drain back? This has been explined. Over filling and or stuck oil return valve.

Solution. Drain all the oil out of the engine and tank, clean up the carb and airbox and so on. Refill the oil tank with the correct volume of oil, turn the engine over a few times without starting and then start the motor. There will be some smoke, hopefully not enough to damage the catalyst. When the engine is hot check the oil level exactly according to hte handbbook.

If the problem reoccurs there is a problem with the return valve: it it is external to the engine probably easy to fix, but if it is integral with the oil pump it is something I'd dump on the dealer. Depends whre you are located.

QED. Thst is exactly the British bike problem. Maybe it also affects less used S&S dry sump units

Also affected all the old Guzzi singles which were dry sump. Usual trick is to put a tap, similar to a fuel tap, in the oil line. Problem is that it is possible to forget to turn the oil on. A length of red ribbon looped around the tap and the handle bar is a good reminder.

Should not be necessary for a modern motor in good condition.

Thank you to all who posted. Well done. Seems my problem was one off and due to sitting for 4 months. No more oil leaked out and yesterday I ran the 3 hard without any issues.