Topic: '77 550K cylinder head o-ring

[Jynx]

First, I'd just like to say what an awesome site this is!  I bought my first (used) bike, a '77 550K about two months ago, and have been watching this site like a hawk.  I'd never had any mechanical or motorcycle experience before, but after I flawlessly walked through a carb clean/rebuild with help from the forums, I thought I'd tackle the notorious leaking head gasket.  From the downloadable service manual, I was able to get the head apart and the gasket changed, but when I was putting it back together, I noticed I had a left over o-ring.  It showed up when I picked up the cylinder head cover, so I would assume it came from there, but can't figure out where it goes.  I couldn't figure it out from the microfiche either.

I also can't seem to find a match, so if it came from where I think it did, I'll have to order another one.  I've included pics of the o-ring and where i THINK it came from.

Everyone locally I talked to (not a single person who's worked on bikes before) said to put it back together and see where the leak is...that's where the o-ring came from.  But I'd rather not spend all that time putting the pieces back together knowing I'm going to have to take it apart again.  Any help would be much appreciated.

Thanks in advance!

[bwaller]

It isn't needed where you show it in your pic. Did you change the base gasket? If you had the head off you should have anyway. That o-ring looks like it should fit around the locating dowel between the cylinder and the upper case. Another possibility is the tach drive o-ring.

[bryanj]

Definately NOT where you show, It does look like a Head or base gasket "O" ring

[edbikerii]

Definitely not on the locating dowel you have placed it on.  There's no need for sealing there.

Perhaps on one of the spigots under the end caps (shiny covers near the top of either side, held on by single phillips-head screw)?
Tachometer drive o-ring (seal is separate)?

Maybe if you looked at one of the online vendors' microfiche you might find o-rings on the parts lists that would point you to it.  Try www.ridenow.com, look for their "partsfinder".

[Jynx]

bryanj and bwaller, you were right...it's from the base gasket.

Finally have another chance to work on the bike, had crap every weekend for a month (wedding season, ya know).

Now that I've got everything back in order (as far as o-rings go) I'm trying to get the cylinder head cover back on.  It won't seem to fit.  If I take the cam shaft off, it fits like a glove, so it's got to be something with that.  The tach screw is all stripped out, so I couldn't get the tach gauge disconnected from the cylinder head, and I'm guessing the teeth just don't line up, but you would think that they would "meet" if i crank the kick starter by hand a couple of times...it doesn't want to.  I've gotten the head on a couple of times and the screws tightened, but when I (slowly) crank the kick starter, it seems to get hung up on something and locks up.  Is there a trick to getting the cover on correctly, or just trial and error until it fits?

[TwoTired]

Do you know about backing off all the valve lash adjusters so they won't catch on the sides of the valve stem during cam cover installation?

If you neglect attention to this, you can bend several rather expensive valve stems.

There is a specific warning to pay attention to this in the Honda Shop Manual.

Cheers,

[Jynx]

Thanks for the quick reply, TwoTired!

I'm assuming you mean the eight little rocker things (mechanically inept, remember!)  I held those back with rubber bands, but still, when I drop the cover on, it seems to have a high point or something, because the whole cover rocks.

[Jynx]

OK, rechecked the manual...in mine they're called valve tappet adjusting screws.  Those are what I held back with rubber bands.

[TwoTired]

As you install the cam cover, high points on the cam will force some of the valves to open.  You have to make absolutely certain that NO side loads are ever presented to the valve stems at the top center of the valve springs.  Rubber bands alone are not a garantee, only an aid.  I also back off all the adjusters so they cannot catch on the side of the stem during assembly.  After cover is installed, then I do the valve lash at each adjuster rotating the engine 180 degrees at a time.

I've gotten the head on a couple of times and the screws tightened, but when I (slowly) crank the kick starter, it seems to get hung up on something and locks up.

I hear this sentence spoken in the voice of doom.  I hope it is only a sound effect and not the real McCoy.

[Jynx]

Got it on...finally.  It took a couple of hours of finagling, but it's on and everything spins freely.  Can't wait to get her up and running!