Hit up a site sponsor. Lots of good ones in here I like Brandon and Shay over to wild ard they do great service! You'll probably want to either send your whole motor to someone or if you can get the pieces out of the bottom you might be able to just do a top end rebuild.
maybe try these? http://67.199.65.66/cascade_innovations/newlook/store/store_View.cfm?STORE_AREA_ID=27&store_dept_id=341 there only 10 bucks so its worth a try. i have them on my bike.