At first I thought it was because I wasn't tightening down the axel enough, but 3 times already I've had to loosen the chain because after riding for a day or two it will be right back right with about 1/2" play in it. Cannot figure out why its doing this. Any ideas?

 

My guess would be not adjusting it correctly in the first place...

If you check several spots of the chain for slack, and you get different measurements, your chain needs a bath in some good cleaner...then a ton of lube...re-intsall and adjust.

Or you may need a new chain.

Or...you didn't tighten the adjusting threads and axle nut correctly.

 

I just ordered a new chain & sprocket set. Enough screwing around with this one. Vortex 520 conv. 15/45 w/ a gold chain.