There are many options to coat your triple.
If you really have to spray due to $ concerns, a readily available/accessible product is rustoleum professional enamel. There are a couple threads on here about it, and there have been good results. Rustoleum also makes self-etching primer in a spray, but you might have to look around to find it in stock somewhere.
Others have tried duplicolor with good results, available at your nearest auto store.
You can also try Westmarine or another boat store that stocks Brightside polyurethane paint. You can buy a small can for about 14$. I just used this on my frame. It dries shiny.