snapped exhaust stud inside gy6 head - Do I need to replace head?

[gidaeon]

Here's a picture of a broken exhaust stud and unsuccessfull attempt to drill into it and use an easy out. It went poorly.. I tried it with engine on the cart. Yeah, I'm no great mechanic.

Suggestions? Should I just research how to remove the head and replace it all together?

After: (I think drilling into it wasn't 100% aligned correctly)


Before:

[ckau]

Aluminum and steel are dissimilar metals. The head is aluminum and the stud is steel. The heat expansion rates are different also. Aluminum expands at a greater rate than steel. You can use this to your advantage by gently heating the area around the broken stud with a heat gun. 9 times out of 10 the aluminum will expand enough to loosen the grip on the steel stud. Heat the area while putting pressure on the stud with the easy-out. If this doesn't work plan B is to drill out the stud. then re-tap for a larger stud. Plan C, replace the head. To perform any of the above plans you will need to remove and re install the head so due to the cost of a head verses the time and effort to save the old one. I'd go for plan C. You did want that performance head anyway, right?

[GX150]

You could go with plan c and then practice your machining and head porting skills on the old one.

[gidaeon]

That is a great idea - thanks!

I was thrilled to see complete heads and cylinders are only $30ea. I am used to more expensive motorcycle parts.

Since the head and jug are already off anyway would you recommend I replace the piston and rings (they are so cheap) as precaution while I'm in there or is that not common? the old rings 'appear' fine and were not stuck.

The jug cylinder wall had no bad scoring, a few horizontal color lines top to bottom and a tiny missing cast chunk near the bottom bevel.