Difficult/Hard starting 80cc 2 Stroke bicycle engine

Benjamin Cox

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Start off with the gas filter...its on upside down...Then replace that crappy, Chinese, Z4C spark plug with something that actually works properly and consistently like an NGK-BR6HS spark plug from your local autoparts store...You also have a problem with the cover to the magneto case, it looks like it is tearing itself open from the inside out in the center of the cover pushing outwards, that can't be good...I have old can openers that can't do that anymore...lol.

I also noticed the choke lever in the full up position which should be full choke "on" postion, yet the hole is unobstructed when it should be totally obstructed when the lever is in the up position.
That lever should be in the full down position for that choke to be totally open in the off postion like the pic shows...This tells me that your choke is not even working because of the lever not actuating the choke mechanism properly...No wonder your having problems starting if you do not even have a properly working choke to start with.

And YES the front motor mount IS an issue...Without that being firmly mounted in place, everything else is going to snap, crackle, and pop like a bowl full of Rice Krispies and milk resulting in a catastrophic failure, and duct tape maybe the handymans best friend but is definitely not a suitable gas tank mounting device...lol.

And this is just a starting point from what I see in the pics...Im sure that others will add their observations to this too.
i went to a few local shops today, none of them said that they have a spark plug that would fit, what is a good one i can get online?
 

Benjamin Cox

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Yes all those things are real issues, the one that is most important is the front mount U-bolt, the rest won't keep it from running. First start by removing the mag side cover and see if it has become loose or in any way messed up or broken. Then put a socket on those head studs and see how many are loose, I see some burnt oil on the exhaust. Once you clear all that up, put in a new plug and try to start it.
ahh yes, i forgot to mention about the crack in the mag cover, yes its correct that the nut came loose and put a crack in the cover, i ended up screwing it back on.
 

weefek

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ahh yes, i forgot to mention about the crack in the mag cover, yes its correct that the nut came loose and put a crack in the cover, i ended up screwing it back on.
did you put it back int the correct orientation? did you lose the woodruff (half moon) key?
 

weefek

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i went to a few local shops today, none of them said that they have a spark plug that would fit, what is a good one i can get online?
the NGK sparkplugs are readily available online. BHR6S, BHR8S, depending on what season it is / your outdoor temperature
 

Benjamin Cox

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the NGK sparkplugs are readily available online. BHR6S, BHR8S, depending on what season it is / your outdoor temperature
can you possibly supply a link to a good spark plug, maybe one that is in Australia? (average temp for me is about 20-32 °c)
 

weefek

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have no clue about you folks down under so i can't link a damn thing but you want an NGK BHR8S. do some searching it shouldn't be hard to find.

I would pull the mag off and check if the key is still there. if you're out of time on the mag it'll never run right
 

Benjamin Cox

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have no clue about you folks down under so i can't link a damn thing but you want an NGK BHR8S. do some searching it shouldn't be hard to find.

I would pull the mag off and check if the key is still there. if you're out of time on the mag it'll never run right
ok, ill look into some spark plugs
 

Chainlube

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ok, ill look into some spark plugs
Go to your local parts store and ask for NGK B6HS sparkplug.

honestly man, i dont know, i dont know much about these kits, i just screwed it back on
Take that cover off and look at the end of the crank where the nut is at, you might have to remove the nut, there will be a notch in one side of the mag. That notch should have a little piece of steel (woodruff key) in it, and that notch should correspond to one on the crank. If those notches are not lined up with each other, your engine won't start.
 
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