i would bolt it on and try it. just be aware that you need to keep an eye on it. also make sure you are listening for changes in the engine while riding. if it does crack there it will cause a base gasket leak and will lean it out. if you ride it with a leaking base gasket for any period of time you will fry it. i dont think nayone is going to say this will be fine, that is a problem for sure. may hold forever, may break as soon as you go to tighten it down. give it a shot. you could always try to find a good local guy to fix it up for you, shouldnt cost too much at the right shop, make some calls and ask around.
For sure keep an eye on it! The manual (online version) says 18ft lbs on the cylinder studs, 20 ft lbs on the head. I am close to those numbers. I'd check it once before every ride for a while.
haven't made a final dissension yet. But looking like I may have it welded. I thought about trying this stuff called quick steel and mold it to the missing piece. my thought is it will give it the extra strength so when tightened it wont brake
i was thinking the same, i say dont chance getting your stuff messed up and do it right the first time, you could do that yourself, id use a stick welder tho