Purchase kfx700 from a family friend that was the original owner. He stated he changed all the fluids before we purchased it. Had it about 1 month checked oil 1 time was fine. Got on today rode about 1/2 mile got on highway gassed it noticed it didn't have it's normal power bogged down and shut off. Pulled it back home checked the oil none on the dipstick. Put 2 quarts in it cranked up just fine at idle sounds great. Ride it and God awful knocking from the right side. In my opinion it's the clutch can hold the front brake gas on it slide the tire and no noise. Took the clutch cover off and I swear it coming from clutch even though I ran without oil showing. Did the belt test looks like I can push it down 1 &1/4". Only upgrades he ever did was a FMF pipe. What do I need to do or check first. Oh no idea where the oil went checked the air box none in there. I only noticed a few drops of oil coming from the rear differential seal.