well when i bought my motor off ebay the seller said no warrantee since it was a high performance engine. after i had the problem with the o ring i asked, didnt insist, to the repalce the head. after i sent the head in he told me to send the rest and he gave me a new engine. (his name in ebay is motorfreak. id recommend him even though he doesnt seem to know much about engines. he thought the head looked fine even though the rockers were melting to the cam lobes. he stands behind his stuff.) im breaking it in right now. im fiddling with the low speed jet to get better response off the line. it seems to hesitate after the clutch is ingaged. just a little bit. after its warmed up its pretty wild. 2nd and 3rd gear wheelies. just throttle. the town i live in is surrounded by a big hill and when i go to work i drive up the hill. before the engine swap it was a 50. i would be going about 15 mph by the time i got to the top and in 2nd gear. better than my bicycle yea, but im used to driving an SV1000s so.....i wanted more. now up the hill in 4th and it can be going 30....just wick the throttle and the pace picks up now. a bit loud for my taste right now. has a visous rap to it.