Stubborn engine mounting bolt - solved!

13 be the one. My bike is a later model than urs so maybe it was something they used later.One other thoght -if u can get a nut rethreaded, a wheel puller as used on steering wheel removal might work as well-anything to give u a mechanical advantage.Good luck and keep us posted..bj

a hand held drill will work I think that's your best bet drill it center with a small bit and step up from there.
heat might work along with penetrating oil,bees wax works good (toilet ring seal) is wax along with heat.
good luck

It's out!
In the end, after all the miracle oils, heating, and brute force had been tried, I mounted my column drill on a low wooden bench so I could get it in line with the front engine mounting bolt. Then I drilled the bolt out with one hand, while sitting outside in the shadow with a lemonade and a cigarette in the other. The drill went through it like butter, I thought it would be way harder.
When I mount the engine in the frame, I'll be using some slightly oversized stainless steel bolts, home-made aluminium mounting plates and lots of anti-seize (copper grease).

For future reference when the next stubborn bolt comes along....

]Better than WD-40