Chain Tensioner Fix
I've read that quite a few Happy Time chain tensioners end up in the spokes, often with disastrous effects.
To prevent this from happening again, simply bolt a 1/4" X 1" X 12"(or so) flat plate onto the tensioner wheel's axle. Then secure both ends to the chainstay/seat stay dropout.
Your Happy Time tensioner will NEVER move out of position again.
I just fabbed a chain tensioner out of a used, slightly grooved ($5) skateboard wheel, ($1)5" of 1/4" X 1" steel plate, ($2)11lb. spring and a($1.59) small turnbuckle. The buckle adjusts spring tension. The wheel has a high-performance ABEC bearing. Even though it's capable of running much higher, the gear ratio keeps the tensioner spinning at less than 600rpm.