Blown Head Gasket

[45u]

You can mill the head and top of cylinder by using a flat piece of glass on a flat surface with some fine lapping compound. You can all so use the glass to check the head and top of cylinder with a feeler gauge.

 

[crassius]

Did the compression ring of the head cut a clean groove in the copper? That sharp cut is what forms the seal, so if the copper was too hard, it may have failed to seal.

Did you look carefully to be sure the head isn't cracked?

 

[45u]

Did the compression ring of the head cut a clean groove in the copper? That sharp cut is what forms the seal, so if the copper was too hard, it may have failed to seal.

Did you look carefully to be sure the head isn't cracked?

This is why you anneal copper gaskets.

 

[Timbone]

There was no marking at all into the copper. I am gonna put a torch to this gasket in minutes! Thanks, guys!

 

[Frankfort MB's]

Can you use copper sealant? Or rtv sealant? Seems like it could hold these little motors, One of my buddies used it everywhere on a drag car making 900hp and it works well

 

[45u]

There was no marking at all into the copper. I am gonna put a torch to this gasket in minutes! Thanks, guys!

This is what is called annealing and been doing it to motorcycle copper head gaskets for 40 plus years. You need to let it get glowing red and let it cool. This swells the copper up and makes the gasket softer. You do not have to get the whole gasket glowing at once just try to get every part of the gasket to glow.

 

[Timbone]

OK. I am rolling again!

I annealed the gasket. Being a pyromaniac, it was fun. Got it as hot as I dared and let it air cool. I could tell the difference.

Replaced the gasket and the cylinder head, clamped it down tight and I got running again. But still, a significant leak directly backwards. No go.

I took the head off my last engine, clamped it down on the new gasket for a test. This thing is in excellent condition with just a bit of carbonization in the combustion area. The bike took off and runs great now. Obviously, the problem is with the cylinder head. I am gonna run like this until there's some kind of problem.

Here are pics:

The blown out part of the gasket (left side) is actually the rear. The leakage was towards the intake.

I can't see any kind of problem with this cylinder head. The leak is on the left side in the picture, which while on the jug aligns with the spark plug hole and back towards the intake.

Any of you experts see something here?

Thanks to all for the great advice and counsel!

=Timbonius=

 

[crassius]

can't really tell from a pic, but I'd guess that head was seriously warped

 

[Frankfort MB's]

Glad you got it running! I've had that same thing happen before as well as a cracked head not fun trying to ride a bicycle without a motor for fat old me

 

[45u]

I have found with the aluminum gaskets every time you stop from riding and let cool the torque is off. This is because aluminum gets hot then cools the aluminum gasket expends and contracts so much. I did try just re-torquing but after a gallon of gas did not change. I do recommend with a copper gasket to re-torque after 20 to 50 miles.

Timbon you can fix your other head like I mention above.
Glade you got back running wish I could ride mine. Nothing wrong problem is I just got out of the hospital Tuesday. But I have drive my rig (motorcycle with sidecar).