I just put together a 400ex and it had a loud valve tick. I adjusted them .005 for exhaust and .004 intake and they ticked. So I went down .001 on each and there was not ticking but the more I rode the worse it got. I also replaced the cam and it was still the same. It has all new valves. Could it be the rocker arms?

 

have the valve seals been replaced? before i rebuilt my warrior it had valve tick even after i had valves professionally done but i rebuilt it ground up do to other issues and all i kept was the same valves because they were good but all seals and gaskets were replaced and now its fine.

 

Cam chain replaced along with the new cam? Cam chain tensioner ok,holding chain tight?

 

May wont to check the oil line from bottom end to see if oiling..crack the banjo bolt at line to head to see it oiling while running...If low oil pressure or no oil may want to check oil filter installation if correct.

 

After it was adjusted down .001 it ran and idled good with no tick. It has good oil pressure, the cam was replaced with one in mint condition and it has good tensioner and new timing chain, valves were done correctly we have done them on a different 400ex and never had a problem with it.

 

The ex's are know for ticking. What kind of cam do have it it? If its a hot cam the tick will be noticeably louder. With a stage 1 or 2 hot cam the valves get adjusted to 13 mm intake 15 mm exhaust.
Hot Cams Products, Inc.