engine suddenly became very hard to turn over

Everything was goin fine,I'm an adult but I am using the bike as my primary mode of transportation for the past 3 or 4 days I have had it.

So today I went across town and chained my bike near the beach when I came back the engine turned over and possibly before it fully stabilized I started up a steep hill, I ended up stopping due to traffic and the engine cut off, after this point I was unable to get it to fully turn over, it will stutter a little and not fully turn on, at one point there was dark colored stuff comeing out of the muffler.

I then waited a few hours and petaled home, there was a steep hill goin down about half way the 6 mile ride so I decided to try one more time to turn it over and it worked. when I got home I stopped the engine and decided to see if I could get it to turn and I had no problem. I then waited a few hours and tried again at this point I could get it to sputter a bit but not fully start.

I am useing 16: 1 mix meaning I mix 8oz per 1gallon of gas so far I have burned about a tank and a half of gas.

Now for the things I know I am doin wrong, I am perhaps riden it a little too hard and I believe its possible 3 in 1 might have been used on the chain.

So what is my move to correct this,? I have been trying to find answers but I cannot.

nothins leakin out of the air cleaner as far as I can tell and I I did check the spark plug after I tryed once and it seemd fairly dry as near as i could tell, I did change out the fuel line yesterday.

so how is this corrected?

so i should drain the tank, lower the mix to around 40:1 which is 3.2oz per gallon if understand correctly and then clean out the needle and cup thingy in the carb, correct?


thanks for your help, I have been enjoining puttering around on this thing since before now.

Ok I drained the tank and cleaned out the needle, I did not see anything in there though. I mixed new gas and now it seems to be starting normally, so yay.


I may not have been 100% accurate with my fule mixture though I probubley added closer to 4oz of oil to my gallon of gas, is that ok?

I was running 16:1 which was apparently too oil rich, I am unsure if the break in period is over yet or not, I think I ran at least one tanks worth of 16:1 fule mix but there was a very tiny leake in the fule line the very first day, would continuing to use 24:1 longer than you have to cause any troubles?

I thought at least the jackdonkeys selling them would know what kinda fuel the engine they are selling took but they don't even know what much apparently.