preparation

I inherited my brothers Murray Track 2 mini bike. He got it in 2004 brand new. The fuel line had dry rotted and I replaced that myself. I haven't been able to locate the owner's manual can anyone give me tips on what I should do to make sure I don't ruin this bike. I cannot get it to start...

I've read conflicting things over the web about 5hp Briggs builds. Is it better to machine down the head on a flathead for compression or leave it alone for maximum flow? Is there any work that can be done to improve flow? Which is preferable with these engines, increased compression or flow...