My 16 year old saved to be able to buy an engine for his bike.. according to the sites measurement information the engine he bought should have fit his bike.... it didn't, so he purchased the recommended mountain bike on bikeberry that was a two week wait. The engine fit barely but after recieveing the bike he had to order a special mounting bracket that wasn't mentioned by customer service. Another 2 week wait later... we got it all put together only to find out the cdi is a dud... so again to customer service who said they were sending another.. 2 weeks later still have not received it and was just told its on back order til??? If you want a chance to return or exchange make sure right out of the box you test the cdi with an ohm meter because once the engine has been mounted they won't let you return it. My poor kid has spent over 600 dollars on a paper weight.