Overheating and losing power

If its close, you can try going one step larger on the jet with a cooler plug.
 
Here's what I would do. If your going to be messing with the engine to get more out of it you may as well take the time and do it right the first time. A little patience at the beginning will save you a lot of time over all. First I would look inside to see if I already caused cylinder damage cause it don't sound good. If no damage I would stick with 1 base gasket, use a after market 6cc performance head to aid in cooling, A NGK B7HS plug, a .8mm copper head gasket. Check squish gap.

To check squish gap use 1/16" rosin core solder taped to top of piston. with engine assembled and torqued turn engine over a few times with plug out. Remove head and measure solder at it's thinnest point. Looking for .8mm below .7 is getting to close over .1 you start to waste fuel.

If you want optimum compression with correct running conditions this is the way to do it. The newer CDH PK80 with rod marked ZL40mm are the same as a Zeda 80 and should be vary close to good with this setup. The stock head especially since you've sanded it won't work like this. The reason being that the crush ring on stock heads extends into the cylinder where as the aftermarket head has 47mm ID crush ring matching the cyls. diameter.

Then again if you just want it to run without over heating, and don't care about best performance conditions do as Spare parts suggested and just replace the second base gasket, and use what you got.
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Gary nailed it as always, but one small thing to add:

If you are running the stock head, you can fix the crush ring using an old piston attached to a drill and some sand paper. I just stuck a bolt through the wrist pin hole of an old piston, welded a stud to it. then put it in a drill in a vice. Taped a strip of sandpaper to the top, then lock it running and gently place the head on top and it will properly shape and clearance the head you can zero deck it and get your ideal squish. With a CNC head you can just mount an old plug in the head and attach to that to spin the head and hold the piston, but you can't do that with a stock slant head for obvious reasons lol.

This is what I did to properly run an A35 moped head, since the tiny stock chamber would physically hit the piston unless I used two head gaskets. Now it matches perfectly (stock on left after removing the little ridges, modded on right). Cools better than the CNC head did and stock length b6hs plug won't shroud in the thread like some of the knockoff CNC heads do.
88750
 
Gary nailed it as always, but one small thing to add:

If you are running the stock head, you can fix the crush ring using an old piston attached to a drill and some sand paper. I just stuck a bolt through the wrist pin hole of an old piston, welded a stud to it. then put it in a drill in a vice. Taped a strip of sandpaper to the top, then lock it running and gently place the head on top and it will properly shape and clearance the head you can zero deck it and get your ideal squish. With a CNC head you can just mount an old plug in the head and attach to that to spin the head and hold the piston, but you can't do that with a stock slant head for obvious reasons lol.

This is what I did to properly run an A35 moped head, since the tiny stock chamber would physically hit the piston unless I used two head gaskets. Now it matches perfectly (stock on left after removing the little ridges, modded on right). Cools better than the CNC head did and stock length b6hs plug won't shroud in the thread like some of the knockoff CNC heads do.
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I was curious about what needed to be done to get that head to work. Now I know, thanks. Do you happen to know the thickness of the a35 head?
 
Gary nailed it as always, but one small thing to add:

If you are running the stock head, you can fix the crush ring using an old piston attached to a drill and some sand paper. I just stuck a bolt through the wrist pin hole of an old piston, welded a stud to it. then put it in a drill in a vice. Taped a strip of sandpaper to the top, then lock it running and gently place the head on top and it will properly shape and clearance the head you can zero deck it and get your ideal squish. With a CNC head you can just mount an old plug in the head and attach to that to spin the head and hold the piston, but you can't do that with a stock slant head for obvious reasons lol.

This is what I did to properly run an A35 moped head, since the tiny stock chamber would physically hit the piston unless I used two head gaskets. Now it matches perfectly (stock on left after removing the little ridges, modded on right). Cools better than the CNC head did and stock length b6hs plug won't shroud in the thread like some of the knockoff CNC heads do.
View attachment 88750
I did something similar with a bolt in a hole drilled through the top center of a piston. Then I bolted the head that had a bad squish angle to a old cylinder, lightly oiled the piston and cyl. and used a drill on the bolt to shape the chamber. That was my answer to no drill press. You could look in the cyl when bolting up the head to see how centered the chamber was. I think I got the idea from Steve Best in 1 of his head experiment posts.
 
I set it to the richest setting its no longer overheating but b4 strokes a lot and knocked my power down a good bit.
 
I was curious about what needed to be done to get that head to work. Now I know, thanks. Do you happen to know the thickness of the a35 head?
In which direction? Quick rough measurement and total height with fins tapers from just under 2" in the front to 2.7" in the rear. Mine is decked roughly 1mm to keep chamber volume down after increasing the squish taper. I can grab the calipers for a more exact measurement in mm if you'd like.

Its huge, so if you already have an expansion pipe it will likely need modding to fit. I did the head before I did my pipe so just worked around it. Downside is that pipe has to come off to remove head.
 
Ju
In which direction? Quick rough measurement and total height with fins tapers from just under 2" in the front to 2.7" in the rear. Mine is decked roughly 1mm to keep chamber volume down after increasing the squish taper. I can grab the calipers for a more exact measurement in mm if you'd like.

Its huge, so if you already have an expansion pipe it will likely need modding to fit. I did the head before I did my pipe so just worked around it. Downside is that pipe has to come off to remove head.
Just a rough estimate is good. I'm limited for clearance so I just needed a rough guesstimate to see if it's even worth trying. Thanks a bunch
 
Damn you Chris, you cant run that head! I was planning on getting one for the new engine to keep the heat down. Maybe even mount it sideways lol.
 
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