apollo 125 will not run, brand new

vsgts14 · 06-08-2021, 03:12 PM

ok guys, I am turning to a forum for help and answers.
Got a new apollo db 125cc bike. arrived, put together, wouldn't start at all. i knew the carbs were junk from the factory, so i got a mikuni vm22.
i installed that, new air filter, bike started first kick with the choke on. as soon as it warmed up, i turned the choke off and it would just die. could not find any leaks anywhere.
started it again with the choke on and it was hesitant and rode it around with the choke on (fuel enrichment). seemed ok, had a lot of smoke from the head pipe and oil was dripping out of it?
thinking it's a fuel/air issue, i tried starting with no choke and a little throttle. well now it had a mind of it's own, and was idling erracticly going super high and then would die off, i tried again and had to kill it because it got really high idling all over the place. at that point, i was stumped.

i figured my fuel was weird, so i drained it from the mikuni and it was greenish. odd because i just filled my gan with amsoil stabilizer in it not too long ago. drained the tank, cleaned out the carb. put it back together with fresh no ethanol 95 octane fuel....no start whatsoever, not even with ether as an aid.

got a new spark plug and new cdi box, put them in, first kick it sounded like it wanted to fire and wouldn't. now if i give it a bit of throttle to start, it will not do anything and at one point, giving throttle kicked the kick starter back up?
guys, i feel dumb and i am not mechanically inclined, i have built subaru motors.

i have a new piston/head on the way cause i feel like it's dead. can anyone help? and can anyone tell me where i should start with the air/fuel mixture and idle screw on the mikuni?

China Rider 27 · 06-08-2021, 05:03 PM

I would do some troubleshooting to determine the cause. First check and see if you have spark, you can take the plug out and ground it against the side of the engine then turn it over and you should see the spark. Second that high erratic idle sounds like your carburetor slide is held open by misalignment in the carburetor or a too tight a throttle cable. Look inside, you will see a pin and on the throttle slide a notch the pin must fit into when installed correctly. Very, very gently so you don't damage the needle turn the idle mixture pilot screw in to lightly seat it and then back it out 1.5 turns. Double check you engine kill switch to be sure it is correct. I would turn the idle speed in to seat it and back it off 2 turns. It it starts and it is idling to high turn it down with the screw.

Big Bird · 06-08-2021, 05:13 PM

What you are doing we call in the automotive world as a 'money bomb'. You need to start with the basics and diagnos for the problem. Fuel, spark, or compression. China bikes will force you to be mechanically inclined cause most places won't touch them for liability reasons.

vsgts14 · 06-08-2021, 05:26 PM

Quote:

Originally Posted by China Rider 27

I would do some troubleshooting to determine the cause. First check and see if you have spark, you can take the plug out and ground it against the side of the engine then turn it over and you should see the spark. Second that high erratic idle sounds like your carburetor slide is held open by misalignment in the carburetor or a too tight a throttle cable. Look inside, you will see a pin and on the throttle slide a notch the pin must fit into when installed correctly. Very, very gently so you don't damage the needle turn the idle mixture pilot screw in to lightly seat it and then back it out 1.5 turns. Double check you engine kill switch to be sure it is correct. I would turn the idle speed in to seat it and back it off 2 turns. It it starts and it is idling to high turn it down with the screw.

referring to the throttle cable being tight, it was working pretty smooth. because i rode the bike perfectly with the choke on, it was fun. but it would not run or start with the choke off, which led me to believe there was a fueling issue.
i pulled the mikuni apart after that and found no evidence of clogged jets or dirt, so that really stumped me. after putting it back together and not having it start at all, really fooled me.

Bruces · 06-08-2021, 06:15 PM

What are the jets you are using in your current carb ? Oh ,the original carbs are not necessarily junk ,and in many cases are no worse than any other clone Mikuni or keihin ,the issues with them are they are jetted really lean for emissions regulations ,so if you can find the proper jets you would of more than likely been just fine .

vsgts14 · 06-09-2021, 10:05 AM

the mikuni vm22 came with a 30 pilot and a 100 main. i am a powersports dealer, so i got it from parts unlimited.

China Rider 27 · 06-09-2021, 10:30 AM

I would go way down on the pilot to a 17.5 or 15. A genuine Mikuni VM22 the choke works backwards of what you think. Pushing it down is choke and pulling it up no choke.

06-08-2021, 03:12 PM	#1
vsgts14 Join Date: Jun 2021 Posts: 3	apollo 125 will not run, brand new ok guys, I am turning to a forum for help and answers. Got a new apollo db 125cc bike. arrived, put together, wouldn't start at all. i knew the carbs were junk from the factory, so i got a mikuni vm22. i installed that, new air filter, bike started first kick with the choke on. as soon as it warmed up, i turned the choke off and it would just die. could not find any leaks anywhere. started it again with the choke on and it was hesitant and rode it around with the choke on (fuel enrichment). seemed ok, had a lot of smoke from the head pipe and oil was dripping out of it? thinking it's a fuel/air issue, i tried starting with no choke and a little throttle. well now it had a mind of it's own, and was idling erracticly going super high and then would die off, i tried again and had to kill it because it got really high idling all over the place. at that point, i was stumped. i figured my fuel was weird, so i drained it from the mikuni and it was greenish. odd because i just filled my gan with amsoil stabilizer in it not too long ago. drained the tank, cleaned out the carb. put it back together with fresh no ethanol 95 octane fuel....no start whatsoever, not even with ether as an aid. got a new spark plug and new cdi box, put them in, first kick it sounded like it wanted to fire and wouldn't. now if i give it a bit of throttle to start, it will not do anything and at one point, giving throttle kicked the kick starter back up? guys, i feel dumb and i am not mechanically inclined, i have built subaru motors. i have a new piston/head on the way cause i feel like it's dead. can anyone help? and can anyone tell me where i should start with the air/fuel mixture and idle screw on the mikuni?
	0

06-08-2021, 05:13 PM	#3
Big Bird Join Date: May 2020 Location: California Posts: 169	What you are doing we call in the automotive world as a 'money bomb'. You need to start with the basics and diagnos for the problem. Fuel, spark, or compression. China bikes will force you to be mechanically inclined cause most places won't touch them for liability reasons. __________________ 2020 Boom Vader Gen 2 2019 CSC TT250 2021 Kayo Fox 70
	1

06-08-2021, 05:03 PM	#2
China Rider 27 Join Date: Dec 2018 Location: PNW Posts: 984	I would do some troubleshooting to determine the cause. First check and see if you have spark, you can take the plug out and ground it against the side of the engine then turn it over and you should see the spark. Second that high erratic idle sounds like your carburetor slide is held open by misalignment in the carburetor or a too tight a throttle cable. Look inside, you will see a pin and on the throttle slide a notch the pin must fit into when installed correctly. Very, very gently so you don't damage the needle turn the idle mixture pilot screw in to lightly seat it and then back it out 1.5 turns. Double check you engine kill switch to be sure it is correct. I would turn the idle speed in to seat it and back it off 2 turns. It it starts and it is idling to high turn it down with the screw.
	0

06-08-2021, 06:15 PM	#5
Bruces Join Date: May 2018 Posts: 1,655	What are the jets you are using in your current carb ? Oh ,the original carbs are not necessarily junk ,and in many cases are no worse than any other clone Mikuni or keihin ,the issues with them are they are jetted really lean for emissions regulations ,so if you can find the proper jets you would of more than likely been just fine .
	0

06-09-2021, 10:05 AM	#6
vsgts14 Join Date: Jun 2021 Posts: 3	the mikuni vm22 came with a 30 pilot and a 100 main. i am a powersports dealer, so i got it from parts unlimited.
	0

06-09-2021, 10:30 AM	#7
China Rider 27 Join Date: Dec 2018 Location: PNW Posts: 984	I would go way down on the pilot to a 17.5 or 15. A genuine Mikuni VM22 the choke works backwards of what you think. Pushing it down is choke and pulling it up no choke.
	0