2000 suzuki 160 quad runner losing power

Hi Guys, Im looking for tech advice on a little quad. First of all I dont have alot of expierence with quads but I love to learn new stuff about small motors. I told the guy I would take a look at it. It hasnt been run in two years. He also said while his son was running it a bolt came out of the engine.(I dont know what that bolt does) I think he ran it low on oil. Here are the symtoms. I rebuilt and installed carb. checked compression. 180psi. Started it and adjusted carb. Then as it warmed up I started to lose power. Then it would not turn over.I hope I explained it right? Any ideas, Anyone. Thanks a bunch. Bruce I looked up what the bolt is called. Its the oil gallery plug.

I hate to ask this but does it have oil and and the plug in it now?

Yes I checked the oil. the sight glass is at half.

First thing, there is no way that quad should be making 180psi. If it is really making that much, something is wrong, your vavle timing may be off. It should only be around 140-150 psi.

Ill recheck compression. Will let you know. Thanks Bruce

I rechecked compression. Throttle wide open, fully charged battery, 6 revolutions of motor, gauge went to 140-150. It will run for awhile, then lose power. Anything I can check without pulling the motor? Thanks Bruce

I would start by checking the valve lash and making sure the carb, fuel tank and petckock are all clean, INSIDE and out.