[dipoco]

Hi just finished my CT70 restoration, installed a 125cc Lifan clone. I got this generic carburator Keihin style so to make story short:
1-by default +/- 1-1/2 air turn. perfect idle but when ran it at mid acceleration stutter like coughing at mid throttle, like too rich.
2-Moved the needle to the max down and the issue reduced 90%. Now still has a soft stutter at mid acceleration, around 3-4k rpm, high acceleration is perfect and idle is perfect too, can be used fine but no perfect, I wish to eliminate this small issue.
Do you think the bike is still running too rich at mid/low acceleration?. in this case which jet is more responsible for the symptom? the main one or the pilot one?.
Main is a #102, pilot has no number, please check pictures attached of the carb and jets. Also checked is there's air leaks and nothing
I appreciate your thoughts and help before I start doing trial and error.
happy 2020 and all the best.??
D.

 

[tmas]

Do you know what size carb it is?
tmas

 

[dipoco]

Hi, it's a 26mm. This is the model. Bike runs great with lot of power and start with one kick, that's the only issue.thanks

26mm CARB CARBURETOR for 110cc 125cc 140cc Pit Dirt Bike Lifan Loncin YX140 Molk | eBay

26mm Carburetor for YX125 YX140 YX150 YX160 Molkt. Works on most 4-stroke quad and pit bike engines YX125 YX140 YX150 YX160. 26mm venturi.

rover.ebay.com

 

[tmas]

Have a look at THIS jetting tips thread.
tmas

 

[dipoco]

Have a look at THIS jetting tips thread.
tmas

Hi Tmas, thanks for this great article. seems like I have to try testing a bit smaller main jets, I'll keep you posted.
have a great 2020!!

 

[dipoco]

Have a look at THIS jetting tips thread.
tmas

Hi, I replaced the original102 jet for a 98, put back needed in the middle and VOALÁ, perfect!!. Thanks, awesome 2020.

 

[Jaydawikid]

Hi, I replaced the original102 jet for a 98, put back needed in the middle and VOALÁ, perfect!!. Thanks, awesome 2020.

Hey bud i have a 125cc lifan and it came with a pz27 carb what whould be the best size cause the 27 stutters in mid to 3/4 throttle like it coughs should i contiue trying to jet it or get a smaller carb and what size should i get. I want it to ripp loke the dirt bike motor it is and it doesnt but i can slowly get on it

 

[dirtbkr188]

Hey bud i have a 125cc lifan and it came with a pz27 carb what whould be the best size cause the 27 stutters in mid to 3/4 throttle like it coughs should i contiue trying to jet it or get a smaller carb and what size should i get. I want it to ripp loke the dirt bike motor it is and it doesnt but i can slowly get on it

Jaydawikid,
Post up some pics of the carb so we can see what you're working with

 

[dipoco]

Hi, I remember resolving a bit similar problem plus backfires with 98 main jet and 15 slow jet, 1-1/4 air screw, needle center ring. Of course you have to do trial and error, also play with the adjustments. It's not same carb but very similar. Also sea level make it a bit different. I am very low under-sea levels lol, Miami.
Good luck.