Advice on new top end

arazzer

New Member
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Jun 8, 2020
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Not sure why (have a couple ideas, will discuss below), but my 80cc "zeda" motorized bike started making some metal noise and bam, stopped running (on my 3rd gallon of gas, fml). I had tried a recommended bp6hix or whatever iridium plug, but that plug protruded too far into the cylinder and got smashed back up, not sure if a piece from the piston got dislodged or what, either way, engine went out and I was left with a giant hill to deal with on my own. I took the top end off and clearly there was some piece of metal causing all types of damage to the cylinder, the piston and the cylinder head. The wrist pin was stuck in the piston and I literally had to hammer it out (hope I didn't mess up the crank at all?) Included some pics, I'm guessing some of you will cringe. Didn't include images of cylinder head but it was also dinged up pretty bad.

I now need to replace the top end, and options are abound on the internet. My engine has a stated stroke of 40mm, does that mean I need a special head or what? I saw a CNC head/top end kit from ebay that is $32 (link below), will this work fine? Is there anything I need to do to make sure my crank is okay? After it broke, there was clearly a loss of compression as I could easily roll the bike forward with the clutch engaged, and even with whatever tiny bit of compression was left, I was able to get the motor going again (at almost no power) and it helped me out as I made my way towards home, and as far as I could tell at that point, the crank seemed to be rotating freely (just hope I didn't damage it removing the wrist pin). Amazing what little power is required for assistance.

Kit I"m looking at:

Engine I purchased:

Number on rod:
ZL40MM

Not sure if I have type A or type B piston
 

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Links to eBay may include affiliate code. If you click on an eBay link and make a purchase, this forum may earn a small commission.
The replacement cylinder and head you picked out only has 32 mm intake spacing, unless it comes with a intake manifold you might want to pick another. The Zeda has 40 mm intake spacing.
 
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