CBX250RS-E Engine Rebuild 10/03/2012

Ah more warmth! Today was barrel day, I was not looking forward to it but it has to be done! First I covered the bore with oil, then the piston rings and then the top edges of the piston, not sure if that was necessary but I had lots of oil to hand. The manual says to then put some liquid gasket on the "meting areaes" where the cases come together around the conrod, then slap the base gasket on (12191-KG0-306, £5). Then put the crank at bottom dead centre and simply squeeze the rings together while sliding the barrel over the top. Even the picture of the bloke doing it in the manual looks like he's having trouble but the two of us (me and my dad) managed it without much drama. I hated torquing it down to 50Nm though, the bolts clicking away like the thread was already stripping. Anyway, the end result was this!

More progress! I then decided to clean the old gasket residue off the head, and when I was about halfway I noticed something that looks bad. Like, horrible at this stage of the game. As in, well..

Both of the cracks are on the left side, I guess this is a result of the dual carb setup even though there is some odd reed valve stuff going on inside the head to try and equal it out. The left side is the primary carb so it gets used more than the right side, and the use of smaller main jets in the past by some idiot has taken its toll. So is this still usable or am I to strip the head off the other engine? I was really hoping this build would last for at least 30K before needing attention, I guess that is out of the question with damage like this? It makes me sad :(

Oil pipe from previous post: £10
Base gasket: £5
Running total: £629.96