Break In Chinese YD100 no power

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Hello! So I bought a chinese YD100 kit from a german seller. Anyways i installed it onto my frame and tried to start it... I spend about 30 minutes trying to start it. Was checking if it was getting fuel, if the plug was wet all those things. It was backfiring like crazy at first. After about 30 minutes it started but would not idle. After about 15 more minutes of trying i got it to idle but the throttle response was non-existent. Again after about 15 more minutes it started responding to my throttle inputs. Tried to ride it and it bogs down when i get it going. I let it run for 15 minutes and rode it on a flat road for about 30 minutes but when i came to a hill i wanted to die so i had to pedal with it. Is it normal that it has no power at all while in break in. Before putting the engine on the frame i checked all of the bolts and such and i found out that it had no gasket between the cylinder and the case (it has a 1 piece cylinder and head). I made my own out of gasket paper. There are no obvious air leaks. The needle pin is set on the 3rd groove from the bottom. Should i try tweaking with the carb first? Thanks in advance!
 
I wonder how OP's motor worked out.... sounds like he got it running but it was still in break-in. Wondering how it's running at this point... someday I'll be going with the YD100 and trying that block out...

I'm really interested in the elevation and c-clip placement on the needle. I too am right in the middle on my NT carby and I'm about 100 to 500 ft above sea level.

I see they got a version 2 out now where it's not a one-piece jug but rather has a head that can separate from the cylinder.
Right now it has 400km on the clock and is running good. Pulls good and sound great! Although my second builds engine pulls a bit better on hills (i would say since the cylinder base gasket is thicker and the timing is better) Im currently also making a trailer and will see how both bikes will pull about 5-50kg of extra weight...
 
Hello! So I bought a chinese YD100 kit from a german seller. Anyways i installed it onto my frame and tried to start it... I spend about 30 minutes trying to start it. Was checking if it was getting fuel, if the plug was wet all those things. It was backfiring like crazy at first. After about 30 minutes it started but would not idle. After about 15 more minutes of trying i got it to idle but the throttle response was non-existent. Again after about 15 more minutes it started responding to my throttle inputs. Tried to ride it and it bogs down when i get it going. I let it run for 15 minutes and rode it on a flat road for about 30 minutes but when i came to a hill i wanted to die so i had to pedal with it. Is it normal that it has no power at all while in break in. Before putting the engine on the frame i checked all of the bolts and such and i found out that it had no gasket between the cylinder and the case (it has a 1 piece cylinder and head). I made my own out of gasket paper. There are no obvious air leaks. The needle pin is set on the 3rd groove from the bottom. Should i try tweaking with the carb first? Thanks in advance!
Yeah try moving it down one more notch. For some reason my bike only runs if it's at the bottom notch. But I would suggest moving the c-clip to each notch on the jet needle just so you know which notch helps your engine run best for sure.
 
Yeah try moving it down one more notch. For some reason my bike only runs if it's at the bottom notch. But I would suggest moving the c-clip to each notch on the jet needle just so you know which notch helps your engine run best for sure.
It looks like your a little "tardy to the party" deuce...Two months later he reported things running OK now.

Right now it has 400km on the clock and is running good. Pulls good and sound great! Although my second builds engine pulls a bit better on hills (i would say since the cylinder base gasket is thicker and the timing is better) Im currently also making a trailer and will see how both bikes will pull about 5-50kg of extra weight...
 
The C clip right now is at the 2nd position from the needle up... my elevation is at about 250-300m
Also what jet size would be best for this 100cc engine?
Was also thinking about sanding down the magnet key so i could adjust timing if that would be a good idea...
Again thanks for all of the help and tips!
It’s your exhaust pipe hole at the end is why it Boggs down drill a few small size holes in the end and the problem dissolves in to nothing but a great running bike engine
 
It’s your exhaust pipe hole at the end is why it Boggs down drill a few small size holes in the end and the problem dissolves in to nothing but a great running bike engine
It’s not the carb it’s the exhaust hole make it bigger or drill some holes
Did you not see that the problem was solved already???

Right now it has 400km on the clock and is running good. Pulls good and sound great! Although my second builds engine pulls a bit better on hills (i would say since the cylinder base gasket is thicker and the timing is better) Im currently also making a trailer and will see how both bikes will pull about 5-50kg of extra weight...
Did you also not see the post back on Aug. 13th 2023, just before your two posts, someone else also made the same mistake of not reading the thread before just replying???

It looks like your a little "tardy to the party" deuce...Two months later he reported things running OK now.
oops my bad. I guess I should start reading the entire threads before i comment from now on 😂.

I am now locking this thread since it has obviously outlived its usefulness and is a magnet for folks not reading before replying.
 
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