My 1st Motored bike build.

Well i finally decided to purchase a engine kit for a beach cruiser. I found the cruiser on facebook marketplace for $25, and it was delivered. turned out to be a brand new bike. As for the engine kit i went with a zeda 80 firestorm. I had one issue with the exhaust. it would not fit around the bikes front downtube. Tryed the motor adapter, didnt like it. ended up finally with a ball peen hammer.it`s there and not touching the frame now. i have not started it yet and still needs the chain on, besides its like 19 f outside. but i plan to get the flexpipe exhaust i guess. also gonna have to take some width out of the handlebars, damn. The wiring i`m hoping is good, it was all plug in play,ha i didnt ground to the frame. Is that necessary? and from where?
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coubob

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So I'm thinking king of adding a base gasket and shaving a bit of the woodruff key under the mag to retard it. Should I just leave it alone.
 

Chainlube

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If you add a base gasket it will increase the squish band, (n).
It's a fine line shaving down that key, it takes some careful math.
 

coubob

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i`ve tryed to find out is if my zeda 80 was suppose to have 2 base gaskets. mine only came with 1. i do have the extra base and head gaskets(ordered separately) but i only used what came with the kit. I dont have anything to check squish. i read on here somewhere with 1 base gasket and the stock head the squish would be to tight unless i put an aftermarket head on. maybe this is why with the stock head on with the sparkplug faceing forward, it sounds like contact or breaking rings or just bad, when i took it apart it was fine , no marks anywhere, it runs good when the plug is pointed rearward, though.
 

coubob

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my friend I sold that motor to had finally got it put on a bike.
 

coubob

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Easiest thing I can imagine is to get a windowed piston and the reed valve. Since you have already got the Zeda 80 with the BoFeng Carburetor, it would be quite similar to what I am now running with my new Phantom 85 which also uses the BoFeng carb and this reed valve assembly.

I'm posting down below The URLs for the reed valve that will will fit the 40 mm intake port on the Zeda and the BoFeng just slides right into the reed valve and fits like a glove.

Just be sure to order the intake gasket with the reed valve if you decide to go this route...After using this the past few days, I am impressed with the setup myself...lol.

Must be used with a windowed piston.




I finally ordered this reed valve and gasket along with a cdhpower 80cc/66cc windowed piston kit.. I hope it fits it , 5mm taller than the one from bicycle engines that out of stock.. the dome on top I think. thanks for the input on which reed, i was going to get the oz but i noticed people were saying things about the carb not fitting. i might end up having to get that low profile air breather and than see how the F2 likes it.
 

DAMIEN1307

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5mm taller than the one from bicycle engines that out of stock.
Think the piston will be an issue? DAMIEN1307
It very well could be...5mm can be a significant amount of difference when I hear and see people on here discussing differences between 0.6mm to 1.5mm.

I can only think of a bible verse here in this case...

Proverbs 15:22 says, “Without counsel, purposes are disappointed: but in the multitude of counselors they are established”

I would be curious to hear what @Chainlube, @ImpulseRocket89, @Greg58, and other more experienced builders would have to say on this, but I have a feeling that 5mm may be too much piston height without having enough head height to go along with it, not to mention how the porting will line up with that particular Zeda 80 jug.

Ps...You mentioned your Zeda 80 had one base gasket for the jug...Mine likewise also had just one so I would say this was normal.
The stock Zeda piston is also a domed piston as well.
 

coubob

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Thank you for the info and I'll just have to find another piston probably, ill just have to wait to see the 5mm might be the skirts on the bottom.
 

ImpulseRocket89

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It very well could be...5mm can be a significant amount of difference when I hear and see people on here discussing differences between 0.6mm to 1.5mm.

I would be curious to hear what @Chainlube, @ImpulseRocket89, @Greg58, and other more experienced builders would have to say on this, but I have a feeling that 5mm may be too much piston height without having enough head height to go along with it, not to mention how the porting will line up with that particular Zeda 80 jug.
So from what I gathered the new piston is 5mm taller due to being domed vs the original piston which I am assuming is a flat top? Are we sure the wrist pin height is the same?

If so then I would be wary of running that piston with a head that has a chamber not shaped for it for two reasons. First is the easy one - the potential for the piston to contact the head. Second is a little less obvious, but if the combustion chamber has a squish band and that squish band is not angled to work with the shape of the piston dome it could cause potential issues that would reduce the efficiency of the engine and increase the thermal load on the piston by trapping air fuel charge to the outside of the cylinder. If the heads squish band is flat and the piston has a dome it will cause the tightest point of the squish band to be away from the edge of the piston and closer to the center. That's even less than ideal than having a big wide open squish gap.
 

DAMIEN1307

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5mm taller than the one from bicycle engines that out of stock.. the dome on top I think.
The stock Zeda piston is also a domed piston as well.
So from what I gathered the new piston is 5mm taller due to being domed vs the original piston which I am assuming is a flat top?
As you can see, that question was already answered and does not apply here since both pistons, The original Zeda 80 piston, as well as the new taller one he ordered, are both domed pistons.

He is going to have to place both of them side by side and compare where exactly is that height difference is coming from as well as seeing if the wrist pin height tells him if he has a high or low hole for attaching it to the crank shaft.
 
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