bbump

Obviously the guy above thinks you are talking about a WAVE RUNNER. I have seen some case repairs (no I do not do that), but you might want to check ebay for the cases that you need. Yamaha made engines and used them for years on a number of different models. The 1977 and 1978 YZ400 engines were identical. As far as your WR500 goes, the engine is identical to ALL Yamaha engine cases back to the 1980 YZ465 (81 IT465). The only difference between the 465 and 490 engines is the larger bore in the 490. Hope this helps.