new to motorized biking. Live in ca. Wanted to get my 16 year old grandson a motor for christmas, I understand that the 2 strokes cannot be shipped or picked up in california. however the 4 strokes can. I was wondering what weight capacity can the 4 stroke take? What kind of hills can they take? Is it better to get a 2 stroke or a 4 stroke. And if I chose a 4 stroke which brand or store should I purchase from. thanks karen