No they will last a long time I have one that's 1 year old and I treat it like the red headed step child. all the rest are real close to a year old and all are running in good shape actually faster and better than when new one bike scares me to go wide open on 40 mph is too fast on a bicycle when I think about the bearing etc that the bike has and it makes me think this is going to hurt crashing on pavement at 30 to 35 mph. I hate road rash but it would look strange to wear leathers on a bicycle at least I think it would.
Don't sweat the 30 day warranty they will brake at 31 days out if they are going to.
If you tear it up we can help and if you can't tear it up we still can help you to tear it up.
These bike engine kits are fun makes you feel like a kid again so the price is money well spent. I have a neighbor who is 82 and took a ride on my bikes the fast one scared the h3ll out of him but now he wants one and is building one.