The engine won't start

[wtfmoments]

I'm a newbie and I spent the Thanksgiving holiday setting up the bike. It ran for the first two days. Yesterday when I was riding I heard a loud pop from the engine, but I still can run and ride for a long time. When I tried it today, the engine stopped starting. I had tried for a long time but it doesn't start at all. (Today is raining hard and the air is very humid. I thought it could be the reason the engine won't start?)

Also, I noticed 3 things on my newly installed engine:
1. The spark plug is already black and greasy
2. Engine head has black oil gathered
3. After trying for a long time today, the exhaust muffler is dripping black fuel on the floor

Please help.

 

[DAMIEN1307]

Cant really see the plug...How about a close up???...From what I can see, the plug looks like one of those three pronged plugs.

I'm not seeing black oil on the head, Is that a pic before this ride???...The reason I ask this is because the head has the "Z" series plug that comes with the kit that would be a single prong plug, not the 3 prong plug I am seeing in the first pic.

Dripping from the pipe is normal, at least during the breakin period when your running a heavier amount of oil in the fuel mix.

 

[Street Ryderz]

All to be expected, the plug is fouling from being oil and fuel rich, accumulation of oil at front corner of head appears to be head gasket and the unspent fuel dripping out the exhaust because it has to go some where!
How thick is your mix? you can use the final ratio you intend to run for your break in tbh probably the best way regardless what the chinese manual says.
Your head bolts have be retorqued every heat cycle for 5 or 6 times maybe, this should stop the leakage showing on the head.
not much you can do about the dripping exhaust just know when running right again it wont do that.
Check for spark, remove sparkplug and ground it to the head or cylinder while you turn it over.
let us know what you find!

 

[wtfmoments]

Cant really see the plug...How about a close up???...From what I can see, the plug looks like one of those three pronged plugs.

I'm not seeing black oil on the head, Is that a pic before this ride???...The reason I ask this is because the head has the "Z" series plug that comes with the kit that would be a single prong plug, not the 3 prong plug I am seeing in the first pic.

Dripping from the pipe is normal, at least during the breakin period when your running a heavier amount of oil in the fuel mix.

1. Spark plug: it is a 3-prong spark plug that comes with the kit.
2. Black oil: it shows at the center of the picture where at the left corner of the engine head. The kit I have is the one I bought from Bikeberry.

 

[DAMIEN1307]

Spark plug: it is a 3-prong spark plug that comes with the kit.

Really?, thats the first I have seen that the kit comes stock with the three prong plug...But it is still one of those Z series Chinese plugs.

Ps...Personally speaking, I have never seen any of those Chinese Z series plugs to ever be worth much and many failures reported with how motors run or don't run has usually been cured just by replacing it with a normal NGK spark plug...There are many posts on this forum that attest to that throughout the years now.

 

[wtfmoments]

All to be expected, the plug is fouling from being oil and fuel rich, accumulation of oil at front corner of head appears to be head gasket and the unspent fuel dripping out the exhaust because it has to go some where!
How thick is your mix? you can use the final ratio you intend to run for your break in tbh probably the best way regardless what the chinese manual says.
Your head bolts have be retorqued every heat cycle for 5 or 6 times maybe, this should stop the leakage showing on the head.
not much you can do about the dripping exhaust just know when running right again it wont do that.
Check for spark, remove sparkplug and ground it to the head or cylinder while you turn it over.
let us know what you find!

Do you mean the gas/lube mix? I bought the kit from bikeberry so I followed their mixing recommendation for the break-in period: 1:16. (1 gallon of gas with 8oz of 2-stroke lube)
Also, I tuned the carburetor needle from the center position to the second knob position from the top. (the needle has 5 knob positions)
Do you think it's necessary to adjust the idle screw for the break-in period?

 

[Street Ryderz]

Do you mean the gas/lube mix? I bought the kit from bikeberry so I followed their mixing recommendation for the break-in period: 1:16. (1 gallon of gas with 8oz of 2-stroke lube)
Also, I tuned the carburetor needle from the center position to the second knob position from the top. (the needle has 5 knob positions)
Do you think it's necessary to adjust the idle screw for the break-in period?

Yes the gas and oil mix at 16:1 is not good, I'd cut that in half and go 32:1, needle position should be fine as described and you set the idle screw to hold the idle rpm you want and that's it done it doesn't change how the engine runs any where else in the rpm range.
you are obviously getting air and fuel as the exhaust shows it going through so you need to check for spark as I mentioned and see what you have?

 

[wtfmoments]

Yes the gas and oil mix at 16:1 is not good, I'd cut that in half and go 32:1, needle position should be fine as described and you set the idle screw to hold the idle rpm you want and that's it done it doesn't change how the engine runs any where else in the rpm range.
you are obviously getting air and fuel as the exhaust shows it going through so you need to check for spark as I mentioned and see what you have?

Thank you!
What would be a good spark plug for this 2-stroke engine (66/80cc) that is widely available?

 

[DAMIEN1307]

Thank you!
What would be a good spark plug for this 2-stroke engine (66/80cc) that is widely available?

NGK-BR6HS

Can also be ordered at Amazon.

https://www.amazon.com/NGK-BR6HS-10-Standard-Spark-Plug/dp/B000F0BYXW/ref=sr_1_5?crid=6UR4CUUWHODP&keywords=NGK-BR6HS+spark+plug&sprefix=ngk-br6hs+spark+plug%2Caps%2C140&sr=8-5

And if you buy them in 4 packs like I do...They are much cheaper per plug this way...13.99 for 4 plugs 3.49 each verus 5.40 for just one plug

Amazon.com

 

[ImpulseRocket]

At the very least if you don't want to run 32:1 for break in do 25:1. It will be fine in either case and will run much much better than 16:1 and definitely not be as messy.