Noobie here. I searched and don't this has been posted so here it goes. I just picked up a non-running '98 YZ 400F. I was told it ran before it was parked last season (no reason to not believe them) and they have not been able to start it. I'm not sure what they tried to fix it but the tank was off, carb was sort of on but not hooked up. Parts of the carb appeared to have been opened, others not, and one of the pilot jets was stuck/broken and needed to be drilled out. Before I get too deep in the carb rebuild how do I know if this is the original 400F carb?