I just cleaned the groups, and decided to run a few sinkshots through them (as I always do after backflushing with cleaner) and dial in this new bean at the same time. The left group runs two ounces in 25 seconds, and the right group runs an ounce and a half at thirty seconds. The brew pressure is identical on both pulls, and just to make sure that it's the groups and not the PF's or baskets, I pulled the shots on the same PF and basket in the respective groups. Same results.
Any idea where to start looking?

Clogged gicleur?

HB wrote:Clogged gicleur?

Thought about that, but wouldn't it be all or nothing? The machine is on a softener, so buildup isn't a suspect (it hasn't been that long since I had the gicleurs out).

Well, logic dictates if the pump is putting out 2 ounces at group 1 and 1.5 ounces at group 2, something is impeding the flow and the gicleur is the most likely suspect. I would test it using a portafilter with needle value / thermofilter under pressure to eliminate "operator error."

HB wrote:Well, logic dictates if the pump is putting out 2 ounces at group 1 and 1.5 ounces at group 2, something is impeding the flow and the gicleur is the most likely suspect. I would test it using a portafilter with needle value / thermofilter under pressure to eliminate "operator error."

While I won't rule out operator error already, and I'm thinking that it might actually go that way I did want to mention that the groups are both set to output two ounces, and I stop them before that if it starts to blonde early. The right group stopped just like it was programmed to, at two ounces, and I stopped the left one at thirty seconds. As I was dialling in the grind, I didn't pay to much attentio0n to the product at that point. It was the first coupla pulls, and I was just seeing what neighborhood I was in while running a 'cleaning shot' through the groups. I'll play more later.