$900 bucks! He saw a Woman come thru the door so he decided to take U for a $$$ ride. DO NOT DEAL WITH THAT SHOP AT ALL! Learn how to turn some wrenches! It is a easy fix. Off come the spark plug wire and take out the spark pugs, then undue the bolts a little on each one. Then when out lift the head off GENTLY! clean up the head base and the head and instal the new gaskets with some (very little) rtv. Ask at a part store what that is. And be sure the insides of the cylinder are clean! Use a computer canned air to blow out the crud. And make sure the cylinder head is clean too. Ask them for de-carbonize spray. Once clean reassemble it. And lay out the parts in the order u took them out! And take digitial pic of before you remove a part and then the next stage. This will help you get it back together in the right order! Go slow! Happy biking!