I'm going to build a new bike with a shift kit from sickbikeparts and a 60/80cc 2 stroke. I just have some questions about it. 1. Has anyone had issues with the 3/32 bicycle chain breaking? 2. What speeds have you gotten in top and bottom gear (also how many teeth are your bikes top and bottom) 3. What is a reliable speedometer that can handle the higher speeds (preferably not a 75 dollar computer) 4. Are tensioners on either side necessary? I've seen mixed opinions. 5. Exactly how much space does the engine with the shift kit take up? My bike is a little smaller than I'd like and it's going to be close I think. Thanks for any insight you have!