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Yz400f head gasket absolutely will not seal

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Back again with a strange issue on my strange bike ūüėí. Long story short its a 99 yz400f with a new 426 cylinder, piston, ss valves, hotcams etc. The 426 swap was done right before i bought it but it came from a questionable mechanic so i tore it down and found missing parts blah blah. The new piston kit and valves etc were installed¬†by myself and nothing else up top has changed otherwise.¬†Anyways ive gone through 2 head gaskets since the rebuild and the bike hasnt even left my garage. Lower cases are flat, gasket surface is flat and clean as can be,¬†followed the manual on torquing the head bolts, new crush washers, no matter what i do¬†with this thing the second i start it up the head gasket and base gasket start leaking water inside and outside. This thing ran great before i tore it down but was missing the cam clips and the wrist pin hole in the piston was scored but the head gasket didnt leak a drop.¬†Never ran into such a problematic gasket in my life. Crappy quality gaskets maybe?¬†First gasket set i believe was vesrah this one is cometic. Getting pretty sick of draining mud out of my bike so any ideas are appreciated!¬†

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Nope i figured it out. The jackass that rebuilt it before me ( previously mentioned questionable mechanic ) used a different dowel that was too long but not long enough to notice with a gasket sitting on it causing the head to sit just a hair higher in one corner. Tore it down replaced the dowel today and it seems to be holding up. He must have tightened the crap out of the head bolts to get it to seal or maybe the old gasket was a little thicker than the ones ive been buying. 

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Once i fit it together without the gasket it was noticeable. The longer dowel is juuuust long enough to not allow the head to sit all the way down. 

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