Head Gasket Cb-1

[Johnser]

Hi there,

Just looking at a CB-1 I've recently been working on and I think the HG has gone.

Symptoms:
-Loss of water from radiator
-"mayo" under cam cover
-Lots of steam/condensation from exhaust on startup
-steam/water droplets coming from cam cover breather when throttle blipped
-Radiator cap seal gone (renewed)
-Fan switch possibly faulty
-Possibly (but not definitely) water getting into oil.

Is there anything sensible to check before I drop the engine and pull the head off to look? friend suggested a faulty oil or water pump, but I'm not convinced and dont know how to check they're operating correctly anyway.

[Wafer_Thin_Ham]

Some steam is normal on start up, does it do it when hot too?

Check your oil cap and filler for mayo.
____________________
My Flickr

[Vincent]

My tip would be to look after the cam cover gasket - you can't get them anymore

As above, look for water/oil mix in the engine and coolant bottle and steam from the exhaust. I've not heard of any head gasket problerms on these bikes before, they're usualy quite robust.

[Johnser]

Thanks for the suggestions.

Well, the first time I got the bike started, after a few mins of tickover the oil was really watery and white. and the dipstick almost overflowing. I put it down to having been stood for a while and perhaps somehow rain could have snuck into the sump.

So I changed the oil and since then have been trying to determine if the level has risen. If it has; its not by much.

I am sure that the reason for the steam on startup (which is more than the normal amount - I have another CB-1 for direct comparison!) is that the cam cover breather is chucking water droplets into the airbox.

When I removed the cam cover (and will be extra careful with the gasket too; cheers for the heads up!) to check valve clearances (all within tolerance), there was loads of mayo buildup there.

Sooo, I guess the question is; could these symptoms be caused by anything else? and is there a less destructive test (as opposed to removing the head) I can do to confirm rather than potentially unnecessarily removing the head.

I'll drop the oil again before I take the engine out and inspect for milkyness

Thanks very much for the help!

[Johnser]

Ok,

so I dropped the oil and there was definitely a slug of water in the bottom.

Got the engine out bar the rear bolt tilted forward enough so I should be able to take the head off without disconnecting all of the gubbinz required to fully remove the engine.

When I removed the cam cover, the top was really mayo-y. This, bearing in mind I cleaned and reinstalled the cover just a few short idle/run sessions ago suggests there is something seriously wrong.

Now, I'm actually hoping its the gasket letting water into the the oil stream somewhere just before it feeds a cam above the head....

.. the alternative scenario I can think of is a cracked head

Any other ideas?

cheers

[Vincent]

Maybe someone didn't bother with anti-freeze. That was a very cold snap we had last winter.

[Johnser]

[Johnser]

Well, we have a winner!

yes, the head had cracked letting water into the cam passage. Cracked on both sides but looks like the majority of the water was coming from one split. Either way, time for a new head or to break the bike. Makes sense for all of the symptoms I've been getting too which is a bit reassuring I suppose.

Thanks for the help and suggestions!

Anyone have a CB-1 head?

cheers!

[Vincent]

[Johnser]

Vincent; Thanks for the offer - there are a couple £50 heads on ebay at the moment it is a gamble but probebly better to go with that than to split your motor if its otherwise in reasonable nick. I might even try welding up the splits in mine seeing as its otherwise scrap.

Cheers!

Gareth

[Robin Milford]

[Johnser]