We're always nice here.
Welcome to the forum. We can probably give you specific infornation if we know what bike and what engine you're planning to use but there is a world of information in our 'Search' area as well. I typed in 'friction drive' and got this result> http://www.google.com/cse?cx=partner...ive&gsc.page=1
You can start there but we're always here to help with specific questions too.
Good luck, have fun and show us what you come up with.