One month passed. I think i already improved the shots comparing the first few miserable days.
I read many posts here. Thanks to everyone contributed. However I still don't think I totally understand how to dial in.

I use HG one grinder and Gaggia Factory G106. I do half pumps and check the temperature before the shot.

It really requires fine grind and doesn't like overdosing. In double basket, I keep my dose range about 12.5 to 14gr, depending on coffee. If more than 14gr, it is more easy to see channeling. Its mostly side channeling. Tamper is right size, it shouldn't be problem. Previously I never had big problems about dosing and distribution with Silvia. My extractions were always decent. I was thinking smaller basket size can make it even more easier. However this is even more difficult for me now. I suspect the high water flow when I first raise the lever, It maybe disturbing the puck.

Previously Silvia espresso range was nearly 3/4 turns from burrs slightly start touching. Now for Gaggia it is around 2/4 turns from the same reference. I don't know if this difference is normal or not.

Regarding the lever pressure, I saw comments, people swear they have the best shots when the machine is almost choked and apply big force on the lever. I also saw other suggestions like 'knife on butter'. I am still experimenting. But all i can say, it doesn't sound right to apply big force on lever to me. I always think the lever should go down with one hand (or 2) weights, without any exertion. So I did more shots in this way. But in this case, the crema doesn't look like what I have seen before. It comes out very thin, dissipating very quickly. However the shots still taste great. Pre-infusion time also change the pressure characteristic dramatically. Today I raised the lever for 13gr Kenya, I realised i forgot to put the cup under. There was no clean cup so I had to wash and rinse one. It took around 15-20 seconds while pre infusion. Finally I hold the lever and it went down itself, no exertion at all. There was almost no crema on top. I would throw it to sink if one month ago. But I didn't. The taste was so great, maybe the best shot I ever taste so far. Now I think I shouldn't compare the shots appearance with other pump machines but can compare the tastes.

I'm experiencing nearly the same difficulties with my "new to me" lever. I'm reluctant to grind much finer because my shots taste so bitter before they go in the sink. I've tried various tamping pressure and purge techniques. In another thread regarding the Olympia Cremina it has been suggested that stale coffee might be the culprit. My local roaster blend was probably at the end of it's two week life just out of the roaster but had been in the freezer for a few days though still under the two week limit. I've just opened a new bag of Red Bird Northern Italian Roast this morning. It's been in the freezer for a week unfortunately. This afternoon I'll tighten up that grind and give it a go. There may be an E-61 machine in my future.

The odd thing about this road we travel is that when the same beans are used for pour over I get good coffee. It's a difficult art.

if the shot tastes bitter, you need to lower the brewing temperature. You may also have channeling problem. (you can make sure with bottomless portafilter)

Adjusting the temperature is very important in these machines. Dr Gary wrote a lot about this in this site. You can search.

Overall, my shots taste really good. I can easily say i won't need to turn on my Silvia again unless I want to compare the shots. I just don't know if i am doing it right or not. Is there anything else to improve? Shots really look like they need to go to sink. No crema, no body. But taste great.

Just a quick note that lack of crema often comes from grinding too fine. Pressure on the lever should be about 30 lbs or a bit less. You can put a scale under the machine to see how hard you're pressing. Dose can be a bit higher, up to 17 gm. The lever should not go down by itself. You want to make sure you are using fresh coffee also.

Skyboltone, did you get your Pavoni Pro up and running? Don't despair and go to the dark side just yet. The learning curve for levers can seem long, but it's well worth it.

Yes, it's up and running. I've got the idle pressure set at 1 bar and I'm going to kick it down the (say) .8 and keep going after it. Nothing even remotely drinkable yet. I'm getting no or nearly no pressure on the lever downstroke. Surprisingly there is more effort on the up-stroke than the down; regardless of grind.

Do you have your piston gaskets installed correctly? Top one should flare on upstroke, bottom one should flare on downstroke.

Yup. I'm certain of it. I'm actually wondering a little bit about the filter basket. As bad off as the rest of that machine was one wonders if it's a bit open? I suppose a guy could slip an Aeropress filter in there and see what happens, but temperature first I think. Dan Straight has kindly offered to come over and straighten me out. He's bringing his Ponte Vecchio Export and Pharos over too. That will be happening here in the next week I'm thinking. Maybe we'll buy a half dozen local roasts and make ourselves caffein sick.

skyboltone wrote:Yes, it's up and running. I've got the idle pressure set at 1 bar and I'm going to kick it down the (say) .8 and keep going after it. Nothing even remotely drinkable yet. I'm getting no or nearly no pressure on the lever downstroke. Surprisingly there is more effort on the up-stroke than the down; regardless of grind.

Best is to do the upstroke until you get water out of the group, let it back down a little, THEN put the portafilter in.

T

Any possibility the gasket on the top of the piston rod needs lube or is damaged. Shouldn't be hard on the upstroke.