I was lucky. I got mine for $500 USD and it ran perfectly. The only issue at the time was the clutch plates were stuck so I did not even try it out. Got it home and drained the oil. It came out green. Hmmm, funny color for oil but been away from dirt bike for 20 something years maybe new oil I had never heard of. Got the clutch cover off and found the source of the oil color was the missing magnesium in the water pump region of the case. Probably my biggest expense was having the JB Weld machined to retore the pump side seal pocket. A whopping $65.00 for machine time. Only other puchases were a front brake cable and a new set of grips
Yeah even back in the '80s this was a problem. I remember buying case halves. You couldn't weld it b/c it was magnesium. If memory serves me right, though that is often not the case, someone, maybe it was Husqvarna, did come up with a fix for the problem; but don't quote me on this. I'd have to see if I could find my notes on the bike. Maybe they switched it over to aluminum so it could be welded? I just don't remember. I do remember this being the one problem with the bike. I would drain the coolant out after every ride and remove the water pump cover so it would dry out. Kind of a PITA.