I didn't actually drill the frame, I secured the motor mount strap to the frame with self drilling screws. Although the crack went through one of the holes that was where the crack ended up not where it started.
With the downtube opened I checked it out pretty well with my mini snake LED light and I couldn't see any other cracks.
I got the patch welded in today (slow day at work
) and it looks pretty good so far. I still have to weld the motor mount strap across the repair and it should be set to ride.
Like I said earlier I have a feeling the crack was there all along, If I'd stripped the entire frame down to bare metal when I did the rear suspension I probably would have found it instead of thinking it was just worn paint from the motor mount.
I wish I'd bookmarked the site I came across a few weeks ago, they had every individual part that I'd salvaged off the suspension bike because if I do end up building a new frame it'll just have to be the front half. It'd be nice to have all new parts instead of having to re-salvage the pivots, etc. off this frame.