I'm not too sure what part you are saying is wrong but the only plastic part I can think of in the pull starter is the pulley that the rope wraps around which are still available for about $50. You can also get a used pull starter, check ebay and put up a post in the classifieds here. A pull starter from other machines will work. As for a list of compatible ones there is…
Trikes-
YTM 200E
YTM 200ERN
YTM225DX
YTM225DR
Quads-
YFM 200
YFM 225
250 timberwolf (I think)
Maybe others too
1984 Yamaha YT 60 Tri Zinger(current project)
1983 Yamaha YTM 200 (rear suspension kit)..... long term project
2004 BMW R1150R
1972 Honda CT 70
2007 Lifan 110