Here's a sad newbie tale:
For my bike project, i wanted to clean my engine up by stripping the flaking paint from the case, covers and finned areas. I had recently acquired a new blasting cabinet, and I figured that would probably be the fastest and easiest way to strip; I search for info on this process but couldn't turn up a lot of info. I had taken most of the covers (clutch, shifter, points, sprocket, cam chain tensioner) off the sides for polishing. After polishing those parts and holding them up to the paint flaked engine case, I decided to proceed with the blasting. With the side covers OFF (I just got them polished) and being careful not the aim the blaster directly into the exposed areas, I blasted away with glass bead. Since the motor was too big to fit in my new cabinet, I just did it in my driveway. That glass bead gets everywhere. After the dust settled, I found some glass bead powder and a few granuals of glass bead resting on the oily surfaces of my shifting mechnisms, clutch basket, and charging rotor. I sprayed the areas down with mineral spirits, then air hosed them clean. I can no longer SEE any traces of the glass bead in the visible parts of those areas.
I then proceeded to remove the head and cylinder block from the motor because they would fit in my blasting cabinet once they were off the motor. I was swapping the orignal head with one I picked up on ebay a few months ago which was recently rebuilt with new valve sealed and lapped valves. Since I didn't want to mess up the valve lapping job or tear up the new vavle seals, I left the springs/valve on the head and proceeded to blast again. I did tape up the oil restricter holes. The other holes appeared to go straight through the head, so I left those open. Again, I sprayed mineral spirits on the springs, then air hosed them. No visible traces of the glass bead were to be seen.
Looking back at the engine case, I began to remove the pistons from the rods so I could remove the carbon deposits. I considered my trusty blast cabinet again, but didn't want to mess up the shiny skirt areas, so I just used a scotch brite wheel on my drill press to remove the carbon. While polishing the piston tops shiny, I managed to break two rings on two different pistons. Now I need new rings and will have to hone the cylinders. Anyway, while putting the pistons back in their orignal locations, I happened to run my finger along the sides of the camchain valley. Sure enough, I found more granuals of glass bead sticking there.
I suspect there is probably more granuals floating around inside my engine. I don't think there is a pile of it in there, but there probably is at least some. Considering this, I decided the remove the springs from my head so I could clean off the valve stems. I laid out a pan of paint thinner next to me so I could drop the springs/retainers/keepers into. Valve stem clead, then springs put back on. When I was done, I found a thin layer of glass bead in the bottom of my pan, but I could have sworn the springs were clean of glass bead before I dropped them in.
I've concluded that glass bead does get EVERYWHERE. My orignal search for cleaning an engine by bead blasting didn't turn up much as I was searching for "bead blasting engine". Upon discovery of glass bead in places I didn't expect, I decided to try looking up "bead blasting engine PROBLEMS". Sure enough, I found plenty of info indicating that this should not be done unless the motor is already completely apart with the cases split. I was hoping to find somewhere that this is not a big problem, and that the glass bead will eventually get trapped in the oil filter. But it's looking like know have the split the case, disassemble and wash every part with soap and hot water. The task seems daunting as this is the deepest I've ever gotten into any type of engine.
I do have a 77 motor on my parts bike that I never heard run (cut up wiring harness on parts bike). By the looks of the gunk collected near the exhaust ports, I think it might need a head gasket at least. Then, that motor also has the flaking paint.
I'm not sure which would be an easier job -split the case and clean the orignal motor or try to get running and swap the parts bike motor. I'm hoping someone can provide some sort of trick that will make this not be such a nightmare.
