Try searching eBay for TW200, BW200, and almost any Yamaha ATV with a 200cc engine. Usually people are selling those for pennies. I cannot confirm if an ATV head will fit but, from what I did research carb and exhaust angles are the same, so you may be good if you find a real cheap one. But make sure you hang on to your cam, just for consistency. I was in your position not too long ago, except with a wrecked valve. Ended up salvaging mine. Best of luck.