I installed a HT on my Schwinn Mountain bike and was riding and having fun for a couple weeks but started having problems getting the thing started. I have verified I have spark, fuel (with air), and compression. I also use the 20:1 ratio mixture with premium gas. I had some backfiring after about a 35 minute ride and thats when my problems started. Could this have damaged the carb. The fuel bowl looks ok but I can smell gas in the cyl and plug. Seems like it's flooding quickly. Anyone out there experience this?