You can try www.cvtech-aab.com. I had my motocross (YZ 250 2 stroke) cylinder rebuild. They are located in Thetford Mines (Quebec) . You ship and they send it back to you in about 10 days (You may also drive). It is about 325$ per cylinder.
"Canadian industry leader, CVTech-AAB inc is specialized in 2 and 4 stroke engine reconditioning. Their expertise in crankshaft reconditionning as well as cylinder resleeving and replating using NIKA-TECH's technology is approved by the industry's OEM. "