Ok, Gotta Replace the head, my exhaust manifold blew off some metal!

his196 said:

So, on my little 48cc skyhawk, GT 2, I broke the exhaust port bolts off, then inserted an oversized screw and self-tapped it a bit to hard, and POP, goes the left side of the entire bolt casing!
Now, I'm stuck with about 5 springs holding the exhaust pipe to the head, and it's leaking bad!
I know I need to replace the head, but haven't a clue how to do it.
A step by step, head only replacement would be great!
Some thoughts?
Thanks in advance.

Click to expand...

The exhaust manifold is attached to the jug. The head is the cover plate the 4 nuts and spark plug go on.

Take the 4 nuts off the 4 studs remove the head. Then the jug will come off as well. Pretty easy.

To put it all back together you will need to realign the piston rings. There will be one tiny pin each ring lines up with. Look at the piston and you will find them. You must align the piston ring to these pins.

Failure to do so will result in a broken ring. Put a coat of motor oil on the parts before reassembling. They make a spring compressor tool to compress the rings I have never used one on these tiny engines.

I simply take two finger nails and do one ring at a time gently sliding the jug back over/on the piston.

Put the cylinder head back on re-torque the head back on in a X pattern sequence to 120 inch pounds . Not all at once do it in stages from lower inch pound intervals.

Things to look for have good gaskets. Make sure the cylinder studs are tight into the block. Mebbe use nylon lock nuts do away with the acorn nuts as some folks have reported they bottom out before tightening.

Some one else will add to this I am sure.

dont forget to change your gaskets, seal them with a little copper rtv gasket sealer

http://www.permatex.com/products/au...mum_temperature_rtv_silicone_gasket_maker.htm

i use it on my head,bottom(jug),and intake gaskets

You can start by looking at this. Then look at the other stickys. they are all at the top of this group of posts in Norm's 2 stroke repair center.
http://motorbicycling.com/f39/motorized-bicycle-engine-top-end-rebuild-297.html
http://motorbicycling.com/f39/bicycle-engine-tear-down-391.html

If Lord Vader's post doesn't show it, NOW will be a good time to do a bit of port matching and cleanup in there... and pay good attention to gasket matching!

For them fellas w/no fingernails, popsicle sticks work, or thin wood strips that will not break up and send chips down in there...

EZ to break the rings if yer a clutz, so EZ DUZ IT !
rc


(I'd like to experiment on welding that cylinder if you would give it up for the shipping cost???? tnx, rc)

No I didn't show the port polishing, this post was for just getting the thing apart and back together again.