Rocker Cover seating

[denisducati750]

I've tried to sit my rocker cover on after new psitons etc, and it won't sit flush against cylinder face. After reading through related areas on here, I took it off and sat it on 100% flat plate glass - it appeared to sit flush which I trust means it's not warped. I've tried joggling it on all sides but it still seems to be pivoting on something that leaves one side or the other with about an eighth of an inch gap between it and the cylinder head face. I've loosened all the valves and pulled them back so they all flop loosely when trying to fit it, so guessing it's not them. Any clues? Thanks, Slug.

 

[TwoManyXS1Bs]

Best to install the camcover with the engine at TDC. One cylinder's cam lobes will be facing down, the other lobes will be up, at overlap, and will cause the rockers to press on the valve stems, even with the adjusters removed. Not a problem, it's normal, just continue to run down the head nuts. It's going to be more pronounced if running elephants foot adjusters.

Another thing to check is the 2 hollow guide dowels. Sometimes they can have little nicks on them, from a history of leverage/removal with diagonal cutters, preventing their full seating...

 

[Spockwerks]

Over the years Yamaha has used those dowel pins in different lengths at various locations, like side covers and in other engines. If it will not go back together check the dowel pins, one could be a little longer than the other.

 

[5twins]

You should be able to loosen the valve adjusting screws up enough so none put pressure on the valve stems. That's the reason for grinding the rockers as part of the elephant foot screw install, so you can back the new screws off enough.