SCARY valve noise

[baz666]

Hello all,
yeah, I'm pretty scared. I started up my 83 GS750ES for the first time since last fall and I got a loud valve noise from it sounds like #1 cylinder.
It sounds like when a header pipe is loose but a lot louder. I checked the header pipe and it seems like it's on firmly.
Does this mean a "dropped valve"? I'm not even sure what that is but I've heard it said often enough with tones like its a terminal illness.
Is there anyway I can test for that? I did a valve adjustment the end of last summer but rode the bike for about a month afterwards until putting it away and it rode great.
Could a valve have slipped down slowly over the winter? Or should I be checking for a crack in the header pipe or what?
Any help at all would be greatly appreciated.
thanks,
baz

[Nessism]

Valves don't drop slowly over time. My guess is your cam chain tensioner is binding. I suggest you pull the valve cover and take a look for anything noticeable. The oil pipe bolts on that model engine tend to snap off so grab with oil lines and wiggle them to make sure the bolts are holding.

[baz666]

Hey Ed,
Thanks so much for getting back to me.
So I take off the valve cover and can I slowly rotate the cam chain to make sure it's not binding? Should I rotate it while the bike is in neutral or should it be in gear to get a full understanding of what's going on?

Also, how do I reset the cam chain tension on an 83 GS750ES?
I know how to do it on my old XJ650 Yam but the GS version seems to be a different type of set up.

And I will check the oil pipe bolts.

thanks again,
baz

[Nicholaschase29]

I over revved my 85 700 (essentially the same engine) and a tappet adjuster screw and nut backed off and made a very loud tapping noise. Make sure they are all tight and adjust your valve clearances while you're in there.