I bought a Grubee Skyhawk 66 cc with a clutch about a year ago and loved it until it decided to completely break down... probably my fault because it was a guinea pig motor amongst some others... now, after receiving an e-mail with a coupon code for $50 off i am thinking it's time to make the new investment. my question is, has anyone had a grubee centrifugal clutch engine, and if so how we do they work? the clutch engine started just about every time, but i felt like there was a lot of extra stress on the engine, mount, and bike frame... that being said, theoretically a pull start should alleviate a majority of my concern, but i need to hear some good things about it before i make the purchase. please pass on any info. about the pro's and con's of either engine and i'll keep posting what i decide to do and then can make judgement of my own.