Heres my 48cc mountain bike that I put together about 6 months ago. I use my 2-stroke on windy or really hot days, when I am too lazy to ride my normal bike.
Everything on the bike is stock except the balloon 26"x2.125" tyres, which replaced my worn out 26"x1.95".
I will probably dismantle the motor and give it a clean up and lubrication since the bolts have loosened enough for me. Ive been meaning to do it for months.