Ok so here's the deal, I invited a buddy of mine (at the time) to bring up his dirt bikes ('00 kx125 and '91 cr80r) to go riding. So we went out riding the trails no problems both bikes running great, I crashed in a puddle while using the Honda cr80r and it stayed running until the time when i believe the carb ran out of gas because it was on its side, so we pulled it up out of the puddle and it started first kick, ran good did some more riding and then rode home and took a little 30 -60 minute break and were back at it, so we go riding down this dirt road and were having fun and got to the end and turned around. After turning around we were about half way back and the bike (cr80r) Boggs and starts to die so I start to drop gears, it was the first time I had ever really ridden so I didn't know what to do. I came to a stop knowing very well that it blew up, so we start walking back to the house and we get pulled over by a cop, the cop talks to us and says he's got no evidence since we weren't riding when he came, so he let us go. We get back to the house and we start into the motor to find the inevitable, the engine was blown due to the main bearing (connecting rod to crankshaft bearing) let go and killed everything inside. My buddy said that he had put in a new piston and ring in the engine last year but did nothing else, he wasn't sure how many hours were on the main bearing because he had never replaced or looked into it when the engine blew up the first time. When engine blew first time pieces of the piston skirt went through the whole engine. So he comes after me saying buy it or fix it, he wanted 675$ for the blown bike so that was out of the question, and the repair was going to be around 400-450$ so I refused to pay because the part that failed should have been replaced when the engine blew up previously. Note: he didnt mix the fuel to the 50:1 ratio it required, just poured some oil in the tank and said good to go. So He had asked me before riding if I'd pay to fix if The bike broke in any way while I was riding, me thinking if I crashed or something causing damage. But I still refused to pay, now he wants to take me to small claims court and wants to sue me for 500$ at an interest rate of 35% a year, I haven't received anything In The mail yet so nothing has come of it so far. What do you guys think was it my fault it blew up or what? Can he win?