You would need a gasket too, and a torque wrench (",) .... there are a few things that can cause this, someone could have rolled the quad or perhaps bumped it, or even drove through ice water when the motor was on max temp ... point is you won't really know, best you can do is give it a proper service, make sure everything is 100%, check the oil you just drained for metal shavings. If there are any red flags you will be able to pick it up easily.
1983 Honda ATC250R
1983 Honda ATC200E BIG RED (sold)
1984 Honda ATC200E BIG RED
1984 Honda ATC200X (sold)
1985 Honda ATC70 x 2
1985 Honda ATC250ES BIG RED
1988 Honda ATC250ES BIG RED
1995 Honda Frankentrike 50cc 2-stroke
2001 Honda TRX90
2004 Honda TRX300EX (sold)
2008 Honda TRX250TM
1976 Suzuki RV90M (sold)
1967 Vespa Primavera 125
1958 Massey Ferguson 35