1969 S: White smoke pulls out rom the carburetors air filter

Hi All.
The bike (engine 0 km. all new) starts very well and sounds good but, stopped on the stand, pulls out white smoke from air filter at idle.
Whith the bike switched off the smoke increases for a while.
The bike has:
-two 930 Amal with cut 2 (i know they should be cut 3!) with 220 main jets and 106 needle;
-Pazon I.E. still set statically to 31 degrees (i will use the flash strobo light later).
Do you think that the iussue could be the oil tank that has (the S type) the oil hole breather that breaths into the air filter system?
Thank you.
Ciao
Piero

Re: 1969 S: White smoke pulls out rom the carburetors air fi

pierodn said:

Do you think that the iussue could be the oil tank that has (the S type) the oil hole breather that breaths into the air filter system?

Click to expand...

An easy way to find out would be to run (and then stop) the engine with the breather pipe disconnected from the filter.

Edit: Thinking about it, there's no flexible pipe to the air filter on an 'S' with the central oil tank, so the engine breather could be disconnected instead.

Re: 1969 S: White smoke pulls out rom the carburetors air fi

I had the same symptom in my 1970 Roadster. I switched from New NGK plugs to the old Champion plugs and the smoke was gone. Did you set the ignition properly? The piston has to be at 31deg advance and not in TDC Position when setting the rotor.

Re: 1969 S: White smoke pulls out rom the carburetors air fi

You may be running a little rich with those #2 slides. What you are seeing is referred to as "stand-off" which is atomized fuel being forced back through the intakes as the pistons rise on compression stroke before the intake valves close fully.

Re: 1969 S: White smoke pulls out rom the carburetors air fi

rivera said:

I had the same symptom in my 1970 Roadster. I switched from New NGK plugs to the old Champion plugs and the smoke was gone. Did you set the ignition properly? The piston has to be at 31deg advance and not in TDC Position when setting the rotor.

Click to expand...

31 degrees from TDC

Re: 1969 S: White smoke pulls out rom the carburetors air fi

L.A.B. said:

pierodn said:

Do you think that the iussue could be the oil tank that has (the S type) the oil hole breather that breaths into the air filter system?

Click to expand...

An easy way to find out would be to run (and then stop) the engine with the breather pipe disconnected from the filter.

Click to expand...

Hi Les,
i will do it.
Ciao
Piero

Re: 1969 S: White smoke pulls out rom the carburetors air fi

Danno said:

You may be running a little rich with those #2 slides. What you are seeing is referred to as "stand-off" which is atomized fuel being forced back through the intakes as the pistons rise on compression stroke before the intake valves close fully.

Click to expand...

I mean,
thank you.
Piero