I *need*, in a bad way, my plumbed in Duetto II to pre-infuse in the middle lever position. Currently no water flows from the group until I lift the lever 5-10 degrees further clockwise (viewed from the right front of the machine) past the pronounced middle detent. The pump does not turn on - the mains water pressure causes the water to flow. I am curious if it is possible to rotate the lever about the cam spindle (my term - part #517697 in the diagram here) this 5-10 degrees counterclockwise so that the "new" middle position corresponds to the point I get water flowing from the grouphead. I can't tell from the diagram is there is any keying on the cam spindle that would prevent this.

I figured this was not possible since the stop corresponds to the movement of the cam inside the grouphead assembly. That is, the cam moving off the lower spring loaded seat to a middle position. However, I have been reading that some machines allow water to flow in this position which must mean that the middle detent is due to some other design feature? Or, are the machines that behave this way simply in possession of some magical cam that lifts the upper seat enough to allow water to flow while still maintaining the positive middle stop? Do I need to lengthen the upper seat leg (again, my term - part #522111 in the diagram) so the cam engages it sooner?

I hope that all made sense. I have never disassembled an E-61 so I am hoping someone can straighten out my crooked thinking. Thanks for lending your thoughts!

Is your machine plumbed in or using the tank?

I don't own a lever E61 - mine's a solenoid - but my understanding is the middle position essentially opens the water path to the coffee before the pump engages. The only way this would allow water in is if your machine is plumbed in, i.e. you have positive water pressure without the pump running. If your machine is drawing from a bucket or water tank it won't do it without a flojet.

You may want to read Is there a purpose for the E61 middle brew lever position?

The e61 pre-infuses by design and is the basis of its patent

Need E-61 type brewhead clarification

E61 Group Espresso Machine: Is its reputation justified?

aaespresso wrote:I *need*, in a bad way, my plumbed in Duetto II to pre-infuse in the middle lever position.

Why? I've played with passive preinfusion (or "extended" preinfusion, if you prefer) and didn't find it worth pursuing.

But if you want to experiment, a no-cost way to play around is simply turning off the machine before lifting the brew lever. That is, prepare the portafilter as usual and just before pulling up the lever, turn off the machine. Lift the lever all the way; the pump will not turn on, but water will flow to the grouphead. To end the passive / extended preinfusion, simply turn the machine back on. The pump will immediately engage. The few seconds the machine is off won't appreciably affect the boiler temperature.

I appreciate everyone taking the time to provide some answers. I have read the E-61 posts - they led me to ask this question. I am also aware of some of the possible "hacks" I could use to accomplish the same thing. I actually considered disconnecting the switch and wiring up an external one to accomplish the same thing. But, I don't want to change anything externally - I simply want to modify the behavior of the lever as described in my post. No real reason other than something else to tweak in that all consuming quest for another tasty shot. Thanks again!

On my Duetto it sticks at this position (few degrees up the middle)... Not sure if all are like this... I don't do it a lot, but play with it from time to time.

The switch that controls the pump can be backed out. There is a retaining nut on the outside and inside of the case. Loosen the nut on the front and tighten the nut on the back. That will recess the switch so the lever cam does not push it until the handle is raised further. So instead of the pump kicking in at 50% it kicks in at say 65% raised.

Depending on the switch design, that could be a bad idea and lead to intermittent operation.

If you guys want to futz with pre-infusing an e61, try cramming enough coffee in the basket so you can pull two doubles, one after the other. The ultimate pre-infusion

cannonfodder wrote:The switch that controls the pump can be backed out. There is a retaining nut on the outside and inside of the case. Loosen the nut on the front and tighten the nut on the back. That will recess the switch so the lever cam does not push it until the handle is raised further. So instead of the pump kicking in at 50% it kicks in at say 65% raised.

I thought about doing that, too. But, I would really like to use that positive stopping position instead of monkeying with getting the lever in just the right spot. I am mostly just curious about the feasibility of it all and, from reading the myriad of posts on the subject, thought some others might also be interested in such a hack.

You could also put an adjustable delay on make relay on the pump. That is what I did on my big two group. You raise the lever to the brew position, mains pressure preinfuses the puck then after X seconds the pump kicks on. Now for the caveat. The lever actuated E61 brew group has built in preinfusion. Once the pump is activated, it takes 5-7 seconds for the pump to fill the expansion chamber in the group. During that time, the puck is slowly infused from mains pressure to pump pressure. If you have an auto E61 group (the solenoid activated version) that process takes much less time, as do rotary pumps. In those instances you may get a larger impact with preinfusion.