New 450er, need help

Hey everyone, I haven't posted in a while but I'm back. Anyways I happened to get a 2008 Trx450er in a trade the other day. I traded two old non-running jet skis and the trailer for the 450er. I only payed $400 for the skis. The quad has Houser +4 a arms, a +4 Lonestar axel, full Dasa pipe, DWT beadlocks, and other less important mods. The quad won't start from the electric starter and will run when bump started into 2nd gear. I keep having to put oil in it every 5 minutes of running because it blows it all out of the top of the head. I'm not sure if it needs new valves or what? Also I've been working on the wiring harness, undoing all the half assed mods the previous owner did. I'm trying to figure out what i can get rid of on the harness if I want a bare bones race quad. I would appreciate and input on any of the problems I'm having. Thanks

Blow by possibly due to worn rings

Yeah, that's what the previous owner said that he thought it might be but he wasn't really sure. I'm getting a new Wiseco top end kit for it. People were telling me to go with a CP or JE but I want to still be able to burn pump gas.

what do you mean by out the top of the head??? where exactly is it coming out?