Very tricky to do these with the engine in the frame as Bryan has already stated but, it can be done. I have done this before in the frame but, not all of them. I used a old exhaust flange drilled out as a guide, then a long drill and a extension on the tap. You will have to use a helicoil as there is not enough meat for a insurt or it is getting close.
If any of the exhaust flange screws snap while trying to remove, then these are a bugger to drill out.
The problem is that you can't just pop the head off a 750 while in the frame, unless it has a frame kit fitted.