I had a DL 50 on my Cap and it was just too much power for me. There are other people that love the combo though.

Not being a fan of Fuji engines I would set my sights on an RCGF 45cc or the go the glow route with an OS 160

Gas is best

The short stroke XYZ 50 is also good, not as wild as a DA/DL and the price is under $300.