Last year my son's new Z120 chain went bad. It was flopping around and pieces were coming off of it. The dealer replaced the chain, sprockets, and tensioner. This year, the chain started making noise again. What is wrong with this setup? It seems the tensioner isn't keeping the chain tight. What's the best fix for this? Can I just change the springs?

Once we did the new spring on my son's sled last year we put this on and works great. Did have to buy a new chain but still using the #420 style stock chain and works great:

http://www.goodwinperformance.com/minisledperformance.asp

part # 430-215

And there are other shops that also carry these. Try Rec Motor also.

Hey Catman thanks for this link lots of good parts here.