I have an 03' yz450 4spd and like it alot exept in the tight stuff, then one weekend at croom ohv park it spit the kick start gear out the back of the crankcase. So I stalled on the build until I found a set of trans gears,shift forks and the shift drum from an 06' wr450 and with wiesco piston, con rod,new cyl,port and valve grind plus some used cases from ebay I was on my way to a woods worthy 5spd and with a big weekend coming up it was crunch time getting it together. I did get it done and the lower 1st really lets me crawl up things I couldnt before and the higher 5th carry's alot more speed. The only problem is a small hole about 1/8th in is drilled on the right side crankcase housing right below the base gasket and cylinder which blows crankcase gases and oil vapor on the head pipe. Is this a wr side case that has this hole or did someone drill this for something or another. any help is appreciated thanks.