Heys Guys I just changed the head gasket on my YZ400 and now that its all together i have no compression or very little. I checked the timing numerous times and it matches the specs in the manual. I not sure what i did wrong. Could it be something simple like the decompression shaft. I did not adjust the valve clearances as they were ok. The timing marks on the cam are spot on but once i put the tensioner on it pulls it very slightly off, is this normal. . Need help as to possible causes, hoping its something simple that i have forgot. I have the cam marks lined up as E-I E-I, when the timing mark is on the I on the crankshft. I just read another post i may have put them on the exhaust stroke. I did not change the base gasket and the valve clearances were only just done.