Itinerant Air-Cooled

You want to get the 205J or 205N with a properly functioning vacuum can! There's lots of pictures in my thread documenting my switch from Baby Webers back to my original dual carbs, here: viewtopic.php?f=3&t=13619

Can I ask another question, for those of you who have functioning Dual Vac cans. At rest, how much space is there between the advance limiter notch on the shaft and the can body?

This rebuild can seem like there's only a couple mm of travel on the advance side before hitting the mechanical limiter, but a 'normal' amount on the retard side. It acts almost like they didn't put the spring back in, or used the wrong shaft or something....

mechanicjay wrote: ↑

Tue Jun 04, 2019 12:57 pm

Can I ask another question, for those of you who have functioning Dual Vac cans. At rest, how much space is there between the advance limiter notch on the shaft and the can body?

This rebuild can seem like there's only a couple mm of travel on the advance side before hitting the mechanical limiter, but a 'normal' amount on the retard side. It acts almost like they didn't put the spring back in, or used the wrong shaft or something....

On a new distributor, the centrifugal advance is only to take the timing from 7.5* to 28*. That is a total advance of only 20 and a half degrees. Because the distributor is rotating only half the distance of the crankshaft, the distributor needs only to move the breaker cam 10*. That is less than half an inch at the tip of the rotor.

The vacuum advance only has to advance the timing 10-12*. That is not much movement.

The vacuum retard moves the whole breaker plate clockwise to knock back the timing from 7.5*BTDC to 10*ATDC on the '73-'74 buses, that is a range of about 18* which is twice that of the advance direction.
Colin