Topic: correct valve cover?

[pinnacle]

i have a 74 cb550 motor i bought to swap out with my 78 that went bust. Now  then two tired and others here suggested switching the valve cover with the one on the 78 as it did not have the wear issues the earlier ones had.i took both them off and they look identical but had different numbers stamped inside the crankcase breather cover the one from the 78 had 12/1 and the one off the 74 had 24/9 . it appears someone has fiddled with engine in the past as it has alot of aftermarket parts  on the bike.could it be they had already switched the valve cover?  the motor after a good bath looks to be in good shape had descent dry compresion #'s with kicking it over only and i have not had it running yet. my only concern was that it had been sitting in the salvage yard with no cover on the points and wonder what kind of shape they are in.should i test anything ahead of time and can i damage anything on the motor if i try and start and there is a fault there?

[dave500]

use the points from your old motor if they are better.put some oil down the sparkplug holes and spin it over by hand and listen for any bad noises,then with ignition off spin it on the starter for 20 seconds and listen again,,id drop the pan and get any sludge out,new oil and filter,the better rocker covers have four little wedge shaped bolts that lock the shafts and keep them from rotating in the housing,ive seen these turned too tight and split the housing aswell!!

[Yoshi823]

The early 550 rocker covers had one rocker shaft per rocker. This was changed to one shaft for every two rockers on the later covers. I found this out as my early 550F1 had a problem with wear in the cover, so I put a later F1/F2 cover on instead of buying the longer shafts.

[bryanj]

Look inside the breather cover, if you can see four nuts on what apear to be studs then it is the later cover.

EDIT should have said the nuts are on the rocker cover in the hole covered up by the breather cover

[lone*X]

What year did the latter valve cover design appear?

[bryanj]

It was a modification part so can be found on many years. If you look up the bulletins on the site somewhere the details are in there