Dual Extruder Blobs with 1.75mm filament

Has anyone here ever had and solved this issue? I figure it has something to do with my retraction settings. It happens when the extruder switches from one nozzle to another.

Anyone have recommendation on how to fix the problem?
Support said the following:
This looks to be back-pressure due to the rate the filament is being fed. The extruder with the black filament also looks to be set too far down.

Unless you have swapped in a 1.75mm nozzle, hotend barrel and 1.75mm specific extruder body and idler arm, you are going to have an air gap, which means that your prints are going to get excess plastic deposition any time there is a vector change and the nozzle pauses in place for a few seconds.

Bummer. That’s what I figured, but since I got really great results with the single extruder I wanted to try my luck with dual extrusion. I wish they’d sell a 1.75 mm version…

You can print one, the files for the body are in devel.lulzbot.com, and you can buy an “ao edition 1.75mm hexagon barrel” kit. At that point you swap in the 1.75mm nozzle that you want, remove the barrel and guide tube from the 3.00mm hotrod and swap in the 1.75mm units, or just install the whole thing, and you are done. To fo a dual extruder you are probably looking at $120 in hotend parts

Better off replacing the whole metal end of the hot end, you need almost all of them for the change from 3 to 1.75 MM.(brass insert/heat-break/cold end.) The heat block is the only thing not changed, and it tends to be thread locked on,

Thanks for the info! I might make that a side project. I feel that when I use the 1.75mm filament that the print quality improves quite a bit.