[lhaluciol]

Hi guys,

Today my valve spring compressor slipped and damaged the gasket surface on the head of my 04' CB600RR.
It is still on the compression chamber side, not really on the gasket surface (see picture) but I wonder how I could repair this?

The valve seat is fine.
JB Weld + sanding will probably not stay long...but I can be wrong.

Thanks for your help!

 

[wibbly]

how the.....

 

[lhaluciol]

Well yeah, it slipped!! I barely pressed it, it's like the head is made out of butter lol
Again, in the picture the valve seat looks damaged but it isn't. the new valve seats properly.

 

[wibbly]

what the **** kind of spring compressor are you using that pokes a huge hole in the head like that.

it looks like you have a big score in the gasket surface which is very very no bueno. maybe a good time to deck the head lol

 

[lhaluciol]

My ego didn't want to say that I just missed the valve! lol
It's on the combustion side, not the gasket. I just don't want to have a hot spot and melt the head...

I wonder if a machine shop can do anything...

 

[wibbly]

I was referring to the big gash in the gasket face beside the hole you made.

 

[lhaluciol]

I was referring to the big gash in the gasket face beside the hole you made.

I see; it's more of a fine scratch. Looks bad on the picture but it's not.

 

[JohnH]

clean up the protruding metal from around the crater. smooth out the edges of the hole and try to make it as smooth as possible. Sharp areas will become hot spots when its under compression and combustion. Hot spots will cause preignition/detonation/knock/ping.

its not ideal. replacing the head is ideal, but it should work. I've had similar damage on car engines that have worked just fine afterwards if this is handled well.

Personally, I'd pull all the other valves, or have a shop do that. then have a machine shop mill the head a bit. Don't go crazy, but a little milling should be done anyways as you have the head off. then clean up the edges of the crater by hand to make sure its smooth.

Have the machine shop check valve guide clearances, replace them if needed, check spring pressures, and replace springs that need it. Clean the chambers very well, clean up the ports. Clean the valves and replace any that are suspect. Put in new valve stem seals. New head gasket and head bolts. Do your best to clean up the top mating surface of the block. Very important to have both the head and the block very clean and flat. these engines are high compression and high revving.

if its in the budget, replace parts with higher performance stuff if you want.