Hi guys!
I'm new to this forum and I think I need your expert help with my YZ465.

I bought this old bike as a restoration project, but the funny thing is that even if this bike from Yamaha was a pure race bike, this specific example somehow was road legal here in Sweden during the 80's! Including lamps, turn signals and speedometer!
I still don't know how this happened, cause today this would be absolutely impossible in our country. I still got the papers and even if the bike hasn't been running in over 30 years, I will have it back on the road asap!

But to the problems. There has been some issue with the kick starter mechanism, with a broken kick idler gear etc. I really don't know how the crankcase is supposed to look, but there's a broken hole in the upper right crank case around the kick mechanism. After thorougly googeling this dilemma I noticed that this is a more or less common problem with the 465.

My question is; have any of you guys faced the same situation before and how did you fix it? Should there maybe be a fabricated hole at all, maybe for some spring fasteners or something? Any way, mine is broken and the hole is clearly from a damage not being there from start.
Is it possible for tig-welding? Or I will better buy a new crank case?
I also noticed the upper axle bore also was welded. I have absoluteley no idea why..

I'll try to attach some pictures!

Please help me 
Thank you very much

Unbroken kick start stop area 1981 YZ465 crankcase image..  However it looks to have the same hole damage as yours from.what can be seen.

I remember this exact issue being discussed here several times over the years. 

Here's one of the threads yamaha-enduros.com/index.php/forums/1977...cker-problems#175365