125 lifan atc70 not running right

[3wheelers]

So I bought a brand new lifan 125 engine off of ebay for my atc70. I Have been having trouble with the wiring. I grounded EVERY green wire. And I have spark. It's a blueish purple spark. What color spark am I supposed to have? It has started a few times, after kicking it over hundreds of times and messing with things. Usually it dies after a couple seconds. But I grounded every green wire and it ran for like a whole minute, and it would rev up also. Then it died cause the gas tank wasn't on. I filled it back up with gas, Now it won't start again? Every time it starts, it won't start back up. So my question is, whats wrong? Why won't it start? What color is my spark supposed to be? Could it be a carb problem? Could the brand new coil be faulty? Please help me. Thanks

[jakep53]

Yeh spark should be blueish have you changed the plug even though it sparks I had a chinese bike sparked great but the plug would not let it run for more than 3 seconds but it sounds like a fuel issue to me.

[MIK6]

I had one do same thing.. the cdi was shot, it still had spark just at wrong time.

[3wheelers]

Thanks for you suggestions. Here's an update, today I went out to mess with it some more. I messed with the carb, I tried a different CDI box, nothing worked. Then I took my grounds off (so they were just hanging) then I tried kicking it over and I got a pop. So then, I put them back on, and it started up. It ran great for like 30 seconds untill I messed with the choke (turned it off) it started spitting gas out backwards and died. Now it won't start again. What could possibly be wrong? It's a brand new lifan 125 engine. New electrical, new carb. It all came as a kit with the engine.

[quicksilver]

Check the valve lash.

[MIK6]

Is the float set rite or maybe stuck? Fluid locked condition?
pouring sooo much gas into carb that its going into the intake and into cylinder? Will run after it sits and drys up alittle?
im a huge believer in KISS keep it simple..... ws know what the last S stands for.. Lol
I start w fuel then spark then exhaust.. suck, bang and blow! Lmao
if fuel is coming out of the carb is got to be have toooo much gas.. can do standbuy tap on bowl and hope needle is just sticking.. or clean the carb and look at float height..

[Jason125m]

Are you using the cheap carb that comes with the engine kit? When I picked mine up a few months ago, it was severely lean, and would not run properly at all. What exhaust are you running? What air filter are you running?

I ended up tossing an OEM 125m carb on it, and it runs flawless, with pitbike exhaust, and UNI pod filter.

[3wheelers]

I have not yet put an air filter on it. My exhaust is pit bike exhaust and is barely hanging on. I still need to get a gasket for it. And yes, the carb is the Chinese one that came with the kit. It does not leak any gas at all. And I don't beleive gas is pouring into cylinder. It's started a few times. So it can't be full of gas. It's got spark. Everything seems to be good. I've taken the spark plug out and kicked it over and it smells like gas.

[briano]

Pull the carb and clean it out good, put the air filter on and tighten the exhaust up. Why do you want to run it with no air cleaner and the exhaust hanging off? That may be part of the problem, running too lean, an air cleaner is a restriction and will change jetting and so will exhaust.

[webbch]

Agree with briano - get the airflow the way you plan to run it before doing anything (other than a simple cleaning) to the carb.

[3wheelers]

The carb is brand new, that's why I haven't tried cleaning it. I don't see how it could be dirty. I have no air cleaner on it because I haven't gotten it in the mail yet. And exhaust is loose cause I'm waiting on an exhaust gasket in the mail. Shouldn't it start fine either way? With or without exhaust and air cleaner? I've run 3 wheelers without either before, and they have always run just fine. But I will get those on as soon as possible. I just don't see how they would be my problem. Cause it should run either way. Maybe just not as good as it should.

[briano]

CLEAN THE CARB. I don't care if it's new or not, it's easy to do and basically free. Then you know it's clean. Pull the drain screw out of the carb bowl and make sure you have good fuel flow, also easy and free.

[MIK6]

A new carb can have the needle stick.. or have the wrong jets in it..
Im pretty sure thats where I would start if I was the guy wrenching on it.
I know im a noob, only own 35ish trikes rite now and well over 60 lifetime. Have worked as a atv mechanic and wrench as a hobby. .on top of that im one of the first 25 members of 3ww.. seen and read alot of similar threads.. lol

[danbur55]

Do you have inline filter?? You put gas in it may have moved trash or rust into new carb

[3wheelers]

Everyone seems to be saying its carb, so I will clean it out. If that doesn't work then I guess I'll move back to wiring. Just seems strange, because I will try to start it, and it won't start, then I will take off grounds and mess with electrical stuff then put them back on and it starts and runs great. Then it won't start again. I bought a new wite harness that is much more simple and is made for a pit bike. I have the same harness on a little 70cc dirt bike I have and it's very simple with no grounds besides the stator of course. So if I install that and it doesn't want to run, I will know it's not a wiring problem. I ordered it from China so it will be a while. In the mean time I will clean out the carb really good. I will get my exhaust on well (I just got the exhaust gasket in the mail) If cleaning carb and new wiring doesn't work. What could be my problem? I'm going to get a 26MM Mikuni carb sometime in the future for it, so I might as well get it if my new wiring and a carb clean doesn't work. I also have tried starting it with the gas tank lid off. Incase it was causing pressure in the tank and not letting gas out. So that isn't an issue.