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View Full Version : Lifan 140cc (1P55FMJ) prepping to add headlights


BlackHornet
03-13-2017, 03:21 PM
Hey guys, been a lurker for a bit now but just joined because I am needing some assistance and I havent been able to find the information by browsing. I am hoping somebody here could shed some light on my issue(s):

I am wanting to add some LED headlights to my pitbike that has a Lifan 140cc motor in it. I pulled the flywheel to check out the stator that it has and it is a 6 pole stator with Black/red, white, green, Blue/white, and yellow wires. The white and Yellow wires are not connected to anything because the bike never had any lights, so I ordered a 4 pin rectifier and hooked it up according to:
TBolt USA Tech Database - TBolt USA, LLC (http://tboltusa.com/store/tech.php?pID=57/Wiring+With+Lights)
the top picture.

Green (Ground) hooked to bottom right pin
yellow is upper right pin
white is lower left pin
Red from the top left pin

I took my multimeter (set on DC) and checked the voltage from the red wire and a chassis ground and got between 8v (idle) and 14.5v (revved)....then I hooked an 18w LED bar to it and at idle it was flickering (LEDs flicker on low voltage) and then when I gave it throttle, it blew the light.

So I started testing other wires with my multimeter set on DC and AC to see what I could possibly find out. I got voltage readings from red to ground, yellow to ground, and white to ground regardless if my digital multimeter was set on AC or DC. I swapped the yellow and white wires on my rectifier and got the same results, just a little lower.

Looking at T-bolts page that I linked, should I try the diagram on the very bottom? Would that mean to make a jumper from the top right pin to the bottom left pin and then leave the white wire coming from the stator not connected?

Is my rectifier messed up?
Is my multimeter messed up, since I was getting readings when set on DC and AC from the same connections?

Any help would be appreciated it.

BlackHornet
03-13-2017, 03:32 PM
I know this pitbike doesnt have a battery on it and so if the red wire coming out of the rectifier is supposed to have no more than 14.XX DC volts to charge the battery, I would think that I could hook the LEDs up to that wire and worst case, I have flickering (LEDs actually pulse and so low voltage slows the pulsing down for our eyes to pick up on) or dim lights at idle...which is fine as long as they brighten up and are on solid at throttle.

jct842
03-13-2017, 03:52 PM
If you do not have a battery in it that may be the total problem. Your bike needs a battery to smooth out the new dc coming out of it. It will absorb the peaks which killed the light bar.

BlackHornet
03-13-2017, 04:06 PM
If you do not have a battery in it that may be the total problem. Your bike needs a battery to smooth out the new dc coming out of it. It will absorb the peaks which killed the light bar.

I thought about this before I ordered the rectifier but shouldnt the DC current coming out of the rectifier be, well, DC current? The LED bar was rated for 9v-32v

BlackHornet
03-13-2017, 05:41 PM
ok, so just went and hooked a 12v battery up to the ground and the red wire (top left pin) and put my voltmeter to the battery, got 6.5v at idle and then 15.98 volts when revved.

I then unplugged the yellow wire which shouldve been (according to my readings) the regulated side of the rectifier. I then checked voltage on the battery and got 18v when revving.

So I then figured that since this is a chinese rectifier, maybe the pins got flipped around internally, so I put the Yellow wire to the top left, red wire was top right, green wire was bottom left and white wire was bottom right....zero voltage on my battery. Would I be correct to say that because I didnt get a reading, the ground wire was on the correct pin to begin with?

Could I conclude that eh rectifier was bad from the get-go?

Mudflap
03-13-2017, 06:25 PM
I use this one on my 140 powered CT90. Ignore the solenoid and starter. In place of the battery I use several capacitors. I run the 35 watt standard headlight from where it says Electrical Accessories which is regulated AC. I also run light loads on DC from the red wire which is connected to the capacitors. Lights are bright, and it has worked great for several years.

http://chinariders.net/picture.php?albumid=118&pictureid=931

humanbeing
03-13-2017, 06:39 PM
Are stator & rec matches?
===
For AC-light http://sanxin.com.cn/Exhibit/exhview.asp?pid=30
ALL dc: http://sanxin.com.cn/Exhibit/exhview.asp?pid=37
===
Traditional mehond:
http://mastercircuits.blogspot.com/2012/07/half-wave-to-full-wave-conversion.html
Lazy man = https://item.taobao.com/item.htm?id=39272228687

BlackHornet
03-13-2017, 11:00 PM
I use this one on my 140 powered CT90. Ignore the solenoid and starter. In place of the battery I use several capacitors. I run the 35 watt standard headlight from where it says Electrical Accessories which is regulated AC. I also run light loads on DC from the red wire which is connected to the capacitors. Lights are bright, and it has worked great for several years.

http://chinariders.net/picture.php?albumid=118&pictureid=931

that is the same diagram I used as well. It still didnt seem to be happy

BlackHornet
03-13-2017, 11:02 PM
Are stator & rec matches?
===
For AC-light http://sanxin.com.cn/Exhibit/exhview.asp?pid=30
ALL dc: http://sanxin.com.cn/Exhibit/exhview.asp?pid=37
===
Traditional mehond:
http://mastercircuits.blogspot.com/2012/07/half-wave-to-full-wave-conversion.html
Lazy man = https://item.taobao.com/item.htm?id=39272228687

I came to the conclusion that my stator was a half-wave...so thats what I ordered. the ground is NOT floated on it.