Just recently purchased the DE HondaGX50 kit. I'm still tweeking it, but one day last week the temp reached 47 degrees here in the northeast so decided to give the bike a try. I have the 1.75 roller installed and reached a speed of 29 mph, but didn't want to over stress the engine the first time out. I've read the different speeds suggested but don't think I will know for certain until the engine is broken in. I have the Maxis 2.5 hookworm filled to 65 psi, as I read that was a pretty good pressure for the friction drive systems. I've already replaced the throttle with an old scram twist shifter with the indexing spring removed and works like a charm, cost was 4 bucks. I know some you have crunched numbers but does anyone have the actural riding experience for the numbers?