CB550 Head Gasket Replacement

[bhorst]

So I finally got my 77 CB550 running and then noticed the head gasket leaking on the left side. It's pretty noticeable and is sending some smoke up too. Its leaking where I assume the head meets the engine block.

From what I can tell, I have to yank the engine to replace the gasket. Is that correct or is it possible to replace it while in the bike?

Can I do just the head gasket or am I needing a bunch of other things? It sat for a long time. Has good compression or did anyway. I haven't tested it since I noticed the leak.

It also looks like it is a huge pain to do this ? Thanks!



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[RobbyD]

You can do it in the frame. If it was me I'd go ahead and do valve seals and clean/lap the valves while you have it apart.

 

[brightrider]

I concur. However, pulling the motor is not as scary as you might first think...and I think that it will be quite difficult to remove/reinstall the cam with the frame in the way. I took the motor out entirely by myself using 2 stools on either side of the bike with a pipe running between. Used some ratchet straps around the pipe and the motor, and slid it out. Motor is about 125 lbs. You can build a little stand out of 2x4's on a bench to stand the motor up. With a buddy or two, getting the motor out can be quite easy and IMHO, is well worth the effort for ease of access.

Definitely do some maintenance while you are in there. AND THIS IS MOST CRITICAL...when you put things back together, use rubber bands to hold the tappets up when reinstalling. Do some Googling on this subject. Even if everything "feels" right, NOT using this method WILL result in bent valves, broken valve guides and other mayhem. There is a great youtube series on the 500/550 engine rebuild...highly recommended. Watch the whole series: https://www.youtube.com/watch?v=dDZS4ZZRyik

 

[crazypj]

There is no need to pull motor to do head gasket on 550. The 'O' ring on oil passageway overheats , goes hard then leaks. I don't generally bother with it ubtil oil is 3 fins down (and drops land on your jeans )
The only permanent cure is to counter-bore for a hollow dowel and use a larger diameter 'O' ring.
Mine leaked about every 18 months until I did the mod. CB500f and CB650 have the same issue.
If you only ride 'gentle' and never red-line, it will last longer (I have modified 550, 591cc, 13,500rpm 8) )