Listen, I know these bikes are not supposed to be the most reliable on the road but DO NOT TRUST Bikeberry to fulfill any type of warrenty! I bought two engines from them. One has been fine, the second was a lemon from day one. Since I had a local motorized bike shop I was able to replace the CDI, (twice), and the clutch lever. The second engine never ran that good to begin with, so after checking everything on this blog troubleshooting and it finally stopping mid ride after the break in period I contacted Bikeberry. Here is the response you can expect from these clowns. You need to figure out the problem we do not replace the engine. The problem IS the engine, now I am not a mechanic and I do not know how to tear down an engine and rebuild. I do not have tools to check for correct compression and I do not know how to rebuild small engines if I did I would have a side business doing so! I have however gone through this kit with a shop mechanic on a brief visit and he could not find anything wrong on the obvious (magneto good, check, wiring soldered check, new cdi check new spark plug, check, new boot (non kit), check,) and I went through it afterwards . Now, this engine is still under their posted warranty, under 200 miles and they refuse to do anything. Do not trust them to back up anything they sell unless it is completely missing from the kit and even then expect a two week wait and a lot of back and forth with some rude staff to get that done. I dropped 400.00 with some extra parts from them and have one functioning bike kit. Get the picture, expensive company to deal with!!!! If you are foolish enough to deal with them GOOD LUCK! I will NEVER trust this company again. I know they sponsor this page but hopefully a few people will read this and go to a company that backs the products they sell. I was actually foolish enough to post I never had a real problem with them. Goes to show you should always wait till the S hits the fan.