Question is if there is any way of cleaning that part without removing the head?
You mean the injector bore?
I just used a few very small bursts of brake cleaner in each bore to clear them. I'd attached a piece of soft sponge to a long screwdriver then pushed it into the hole and spun it around as I pulled it back out. Went in clean, came out dirty so that worked well imo. Most of the brake clean should evaporate but there'll be a few coughs and splutters on first start up as the rest is mixed with the air and fuel. All the crap should get blasted through the exhaust ports. It's not ideal but do you really want to take the head off? I can't think of a bigger job given these are chain driven engines.
I made sure the injectors were really clean before I put them back in and applied a thin film of copper grease to the shaft. Makes getting them out next time a little easier.