Cylinder coolant leak on a 1999 Honda shadow ACE 750cc from the tube between the cylinders. Can I fix it without having to take the engine apart?

I don't know about this particular model of Shadow but most bikes have seals on the tube mouting ports, aka the pipes that are bolted to the engine and allow the tubes to be secured to the cooling system. If it's just a seal leak you might be able to very carefully (this may take several hourse of gently turning a wrench, if you strip the bolts you WILL have to take the engine apart, and that's probably gonna cost you a couple of hundred bucks minimum) unscrew the mounts, take the piece out, replace the seals, and screw it all back together. Good luck and check your manual!