I have a 2013 grizzly 700 after changing the spark plug and cleaning the air filter and checking the fuel injector I put everything back together and started it up. It started and ran fine but after about 5 mins of riding the oil check plug blew out and spewed oil every where. What would cause the oil pressure to build like that and not release, the owners Manuel is no help. I assume there's a pressure valve somewhere but I've checked the internet and so far no luck. Any advice would be appreciated
That's not an oil pressure problem. That's a crankcase pressure problem, which s a completely different issue. I would start with inspecting the crankcase vent. I believe on the 700 it might be a PCV valve...not 100% sure on that though.
Welcome to GC and X2 on what dezz said...you're problem is a crankcase pressure problem not an oil pressure problem. If you didn't have this issue before you worked on it then you might have caused it like pinching the vent line.