I'm in the process of cleaning up my Batavus engine and getting all the carbon build-up out of the port. Its a freakin pain to scrape out. A guy at work mentioned to get a grinder attatchment for my drill and just grind it all out with that. He said that its good to get it as clean as possible (even little uneven bumps and stuff) and it should be real smooth for the best airflow. Is it okay to use a grinder on it?
BTW, if anyone's been following my other posts, I brought the head into a machine shop and they are fixing the spark plug heads and putting some kind of permanent insert in it. It will be such a luxury to have the right size spark plug!! Thanks yet again for all your advice.