could I use a car tranny cooler for my big bear? the oil coolers on ebay are 250$(one thats 100 but its a 1991 so idk if it fits)

 

No reason you couldn't if you can figure a way to hook it up. I assume that model already has an oil cooler so the plumbing is already there?

 

Yep, asked the local yamaha dealer parts guy today and he said I could use any cooler as long as I can get it hooked up to the oil filter cap(where the lines go to).

Might try the transmission route depends how cheap they are.