I just recently replaced my flywheel on my 87 500 because the keys snapped off the flywheel and now it won't start I was told that timing might be off but I'm not sure how to do this could some one give me a few pointers on this thanks

With other small engines a mark is sometimes hard to see or maybe painted over, dirty, you might not be at the right angle to see it like on a sled. A scribe or a light tap with a cold chisel and brass hammer before takin apart a running mill is a nice headache saver later on.