I thought it would be a good idea to make a thread about components that should be replaced before installing the kit, since as we know the parts that come on the kits and bikes usually aren't of the best quality. This includes both parts from the kit and parts on the bike. I installed at 2-stroke on my old(relatively) mountain bike, and here are the parts that I've replaced so far: - Mount studs and bolts. I really had to pay the price for not doing this in the first place. - Axles. I have no idea why my rear one bent, but it seems like the new one I bought is much stronger. Decent axles don't seem to be very expensive either. - Fuel filter. I haven't replaced mine yet, but that's probably the next thing I'll be doing. It's okay but I looked closely at it yesterday and saw some sediment at the bottom that passed through the actual filter part. I immediately cleaned it out. I've heard that some people replace their kill switch, but mine seems to work just fine. Here's a list I'll be updating from people's posts in this thread: EDIT: As a further note, anyone who's considering building a motorized bike should feel free to use their own judgment when considering the advice in this thread. Not all of the replacements are 100% necessary to get a bike working.