Hi I am a newbie to HB from Australia.

Our main machine is a Diadema Junior Plus 1 Gp Hx which I gather is sold as a La Valentina in the US.

I recently bought a 1997 Brasillia Portofino 2Gp Semiauto at a local auction which I was able to get back into action after a serious descale, replacement of various gaskets and shower screens etc. This one has the Brasillia Type 1 groups which predate the E61. The curious thing about this machine is that it has different gigleurs (jets) in the top of each of the groups. The first has what I believe is standard with what I believe is a 0.8mm jet. The second group appears to have been drilled out and tapped to fit a larger gigleur with a smaller jet (I suspect 0.6mm).

The machine works fine but the first group (0.8mm gigleur) appears to produce much more crema.

I have a number of questions about this.

1. I assume the machine has been modded. Can anyone give a clue as to why anyone would do this?

2. Is the reason why we can get much better crema on the first group because the jet size is optimized to the machine or is it to do with our technique (eg do we need to let it run longer on the second group) etc?

The machine seems to operating perfectly in all other respects with the gauge reading about 9 bar while making a shot.

I can easily drill out the second gigleur to 0.8mm if that is the thing to do but my instinct is that there may be a valid reason why a previous owner would do this to the machine.

The Brasillia is now our Verandah entertainment machine which will only be used intermittently. Too big for indoors. I must admit I bought it partly because old commercial machines sell cheap here and I wanted a machine to play with which I was not game to do with the Diadema which we bought new. I got lucky because the Brasillia is a pleasure to work on even for a novice and nothing expensive had failed. The worst thing was that the scale had blocked the second gigleur. I particularly like the boiler drain tap which allows me to quickly drain the boiler when it is not being used for a while.

Regards
Ted

Group jets are a way of restricting the flow into the basket. On a rotary pump machine it gives you a slightly longer pressure ramp (very slightly) and reduces the water debit of the group (flow rate). You can pull perfectly good shots from a machine with the jet removed but your technique has to be spot on. The high flow rate has no forgiveness for flaws in grind/distribution. I have used a 3 group LM with no jets installed and did not know they were missing until the owner told me. It was an intentional experiment.

On a heat exchanger machine, it will increase your cooling flush time since the water flow out of the group is restricted. I played around with group jets on my Elektra a few years ago. I just happen to have re jetted the carbs on my motorcycle a week or two before. The group jet looked just like my carb primary jet so I tried installing one and to my surprise, the thread size was the same. Elektra only made one size jet so there was no changing it and I think it was a 0.8 as well. I ended up getting a Keigin carb primary jet from my bike shop that was the equivalent of a 0.6 (if I remember correctly) and have been using it for years now. So, before you go drilling out jets, try your local motorcycle shop. Carb jets are all of $3

cannonfodder wrote:I ended up getting a Keigin carb primary jet from my bike shop that was the equivalent of a 0.6 (if I remember correctly) and have been using it for years now. So, before you go drilling out jets, try your local motorcycle shop. Carb jets are all of $3

Nice tip, I not surprised they might be interchangeable.. but had never considered it before. I'll have to check the parts drawers...

cannonfodder wrote:Group jets are a way of restricting the flow into the basket. On a rotary pump machine it gives you a slightly longer pressure ramp (very slightly) and reduces the water debit of the group (flow rate). You can pull perfectly good shots from a machine with the jet removed but your technique has to be spot on. The high flow rate has no forgiveness for flaws in grind/distribution. I have used a 3 group LM with no jets installed and did not know they were missing until the owner told me. It was an intentional experiment.

On a heat exchanger machine, it will increase your cooling flush time since the water flow out of the group is restricted. I played around with group jets on my Elektra a few years ago. I just happen to have re jetted the carbs on my motorcycle a week or two before. The group jet looked just like my carb primary jet so I tried installing one and to my surprise, the thread size was the same. Elektra only made one size jet so there was no changing it and I think it was a 0.8 as well. I ended up getting a Keigin carb primary jet from my bike shop that was the equivalent of a 0.6 (if I remember correctly) and have been using it for years now. So, before you go drilling out jets, try your local motorcycle shop. Carb jets are all of $3

Cannonfodder, thank you very much. It looks as if the second GP was deliberately drilled out and tapped probably to fit a 0.6 mm carb jet. Will check out the local bike shop to see if I can get a few different ones to try. Anyway pulled some more shots on that Group and now seem to be able to get good crema so it might best be left alone. The important thing seems to me to be aware of what and why is going on and adjust your technique for it. I believe your advice has put me in the position where I can now do that with confidence.