a gp1200 is a 2stroke motor. the only valves that are in them are reed valves and they make no difference. you either have them or you dont. a 2stroke will run either way. they just run better with the reed valves in. the 1200cc 2stroke used in the carbureted 1200s had a fairly low compression ratio (somewhere between 7-8:1). for this matter you could probably get away with running midgrade fuel seeing as how i doubt the head stepped up the compression that much. but i do reccomend that you run premium fuel in any 2stroke engine. otherwise you may start to see the fuel precombust in the air-pump (crankcase) while it is building up pressure to scavenge the exhaust gasses. this precombustion in the crank case will fight the engines natural power. (there are those who may disagree with me but i have seen first hand a 2stroke with a cracked block spit out white smoke from the block so it can and a lot of times does happen depending on which engine ur dealing with)i just purhcased a 97 gp1200with ride plte solas impeller and riva racing head. i was wondering if with this head were the valves replaced and do i need to run a higher octane fuel?