Topic: leaky head gasket :(

[78 k550]

Hey All,
 been doing lots of riding but I think I wore it out. it is blowing alot of smoke out my pipe (blue smoke) It is embarassing at night. I did a compression test only on the outer cyclinders. I don't have a adapter that threads into the small spark plug holes. My dad has one that you hold over the hole and it reads. It is kinda curved and I can only get the outer 2. 1=125lbs and 4=125lbs it runs smooth so I'm guessing/hopeing the other 2 are the same. With that kinda compression it looks like I'll not need a bore. I guess there are some internal oil seals that drie up and cause what is happening with mine. It looks like I blew an upper head gasket but have not lost any compression. Look's like my smoking is with my valve guide seal's if my compression is 125 across the board. Look's like I have a project this winter.

Thank's
 Paul

[SteveD CB500F]

125psi isn't brilliant but it's OK.
You do need to check the other two cylinders though. If you have a K then you must be able to tell which cylinders are smoking (?) - or do you have a 4-1?

If you have a leaking head gasket then you are going to have to strip it off anyway so may as well replace valve stem oil seals.

[78 k550]

yes I have a 4/1 exhaust.
What is a good compression?
My plugs also have a little white on them. Somehow they don't look normal, but not sure how to read them.

[SteveD CB500F]

Well, with a compression ratio of 9.0:1 I would expect 132.3 psi (9.0 x 14.7 at sea level)

I'm sure someone out there will shoot me down if this is wrong.

My 500 runs fine on only 110psi...

[bryanj]

If its blue smoking its normally piston/rings on the 550 and these for the 550 are not as easy as the 500 BUT a 3mm o/s overbore kit for a 500 (550 kit on ebay) is a 2nd o/s (0.5mm) kit for a 550