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KFX 450R knock Rattle help!!

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Hey guys I have a 2008 KFX 450R and just got a new FCI intake installed on it and went out for the first trip of the year to the little sierra sand dunes unfortunetly I didnt get to ride very long, I started to notice it seemed like I was loosing power so I came to a stop and then went to go again and had to rev the machine pretty high to take off almost like I was in 4th gear trying to start out but I was in 1st gear then shortly after the noise begun, rattle and knock almost sounded like the entire motor was going to blow into pices so I shut her down took it home and tore it down took the head and cylinder off and the valves cylinder piston crank everthing looks good I thought for sure with all the racket I had to have sucked a valve or broke the connecting rod but no its all in great shape also keep in mind the machine only has around 30 hours on it. any ideas should I just put it back together??? and see what happens im baffeled thanks for any input or help!!!

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did you buy it new or used? If it was used it sounds like the person before you might not have taken care of it the way it's suppose. I have heard of the stock bottom ends blowing out after guys put in a high comp piston and a big bore kits. Are you sure it's not the clutch giving you fits cause that sounds like the problem initially. And when you changed the oil are there any metal shaving?

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I bought it new I am just a idiot and got in two big of a hurry and put the oil filter in backwards which restriced the oil flow and wiped out the bottom bearing in the rod hopefully that is all that is wrong with it so far everything looks good and I am going to split the case this weekend so I can pull the crank and get it rebuilt, after riding and working on bikes&atvs for over 20years you would think I could atleast change the oil I cant belive I made such a dumb mistake but I guess that is one expensive mistake that tought me to slow down and make sure things are done right, I hope I will be sure to never make this mistake again.

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