LIFAN 140CC NO SPARK

[sdb302]

Hi All

New to site and mini bikes! just purchased a trial bike with a LIFAN 140cc engine which will not start it has NO SPARK, it has a 5 pin CDI i will list the steps I have taken to sort the problem!!

1 killl swith removed wires joined together
2 fitted coil unit to another bike (this bike ran no problems with coil from non running bike 140cc with no spark.
3 fitted extra earth point to coil earth lead (to frame)
4 removed magneto/stator cover check wires attached all ok
5 tested ac voltage from mag/stator red/black wire and blue/white wire, volt meter measured around 40volts when kicked over (checked this against the running bike which also had around 40volts when kicked)
6 tested the resistance of the mg/stator same wires as above measured 470 ohms, the running bike showed 370 ohms but this bike is a 125cc lifan engine.

So Im at the point where Im not 100% sure if the fault lies with the CDI or the mag/stator Im thinking that it maybe the CDI as its getting an ac voltage??

Any help I will be very grateful,
Regards
Stuart

 

[rotn50]

Test the pickup wire from the stator blue and white, hook it up to the multimeter and run the magneto magnet past the pickup, obviously it should beep each time it passes, if continuous non pausing beep or no beep at all pickup is dead. Also unhook the killswitch incase it is faulty, earth the plug out and look inside the plug when kicking it as it maybe faulty sparking inside. Def could be the CDI mate. Welcome dude

 

[my67xr]

welcome to miniriders,

re #1 of the things you have done,

quote " 1 killl swith removed wires joined together"

if you have joined the 2x wires, this will constantly kill any spark
disconnect them and try again for spark
post up your results

 

[rotn50]

My bad, thought terminal was removed and wires soldered, those 2 wires joined will kill all spark.

 

[sdb302]

Hi Guys

I have pulled apart the kill switch wires still no spark (i have a spark tester fitted between the spark plug and the lead which lights up when you have a spark a bit easier than trying to ground the plug!)

Hi rotn50 I tested the blue/white wire as you suggested but could I just run through how I did this with you? I put the multimeter on continuity test (beeps when circuit ok) put red lead onto blue/white wire and black lead to engine/frame at this point the meter reads 134 this reading stayed the same (+/-5) when I rotated the motor slowly on the kick start (by hand) the meter didn't beep at all.

So does this mean I need a new mag/stator? as the pick up is part of that assembly?
I was hopeful it was the CDI as removing the mag/stator looks like an interesting job if you dont have the correct tools!
Thanks
Stuart

 

[my67xr]

turn the flywheel around until the little raised tab on it, lines up with the centre of the pick at the back of the stator.
how much gap do you have between the centre of the pick up, to the little tab on the flywheel?
it should be about a .1 to a .4mm gap there.

 

[my67xr]

i think the 470 Ohms reading from the black/red stripe wire and earth is a bit high a resistance.
normally they read around 350 Ohms when cold, and up around 380 Ohms when warm.

the 134 Ohms reading off the blue/white stripe wire is a bit high too, normally they are around 100 Ohms
so the higher resistances could be stressing the cdi unit a bit too?
i have just checked out a couple of my stators and confirmed those readings too.
the way you tested it, wasnt for continuity either, that reading is resistance, measured in Ohms.

the CDI's run off an AC voltage, unless it has a 150 Lifan type outer rotor fitted, they use a smaller diameter flywheel and have an 8 pin cdi unit.

can you swap the CDI unit off your other bike over to the non running bike?

it might be worth checking the wiring between the cdi and the coil too, i have seen a couple of bikes with broken wires there.

use your meter set to continuity again, put the red lead into the cdi plug and the other end to your coils' positive connection, check there are no breaks in the wire when you wiggle it etc..

the earth wire from the cdi is going to a decent earth on the frame too?

and is there another kill switch on the underside of the front brake lever, some older bikes wont start if you dont hold the front brake on.

 

[sdb302]

Hi Guys

I have pulled apart the kill switch wires still no spark (i have a spark tester fitted between the spark plug and the lead which lights up when you have a spark a bit easier than trying to ground the plug!)

Hi rotn50 I tested the blue/white wire as you suggested but could I just run through how I did this with you? I put the multimeter on continuity test (beeps when circuit ok) put red lead onto blue/white wire and black lead to engine/frame at this point the meter reads 134 this reading stayed the same (+/-5) when I rotated the motor slowly on the kick start (by hand) the meter didn't beep at all.

So does this mean I need a new mag/stator? as the pick up is part of that assembly?
I was hopeful it was the CDI as removing the mag/stator looks like an interesting job if you dont have the correct tools!
Thanks
Stuart

 

[sdb302]

hi Guys

Right I have checked the gap between the tab on the flywheel and the center of the pick up it is 0.1mm so this should be ok?

The CDI on the running bike has a different plug type on it! so couldn't try it on the non runner!

The wiring on the coil checked out all ok, earth wiring to frame all ok.

No signs of another kill switch on the brake lever.

The wiring on the non runner bike is a bit of a mess! been fiddled with before I got the bike, the previous owner didnt seem to know the bike had a kill switch on the handle bar (which is broken anyway) so not sure how they stopped the bike!

I may buy a CDI and mag/stator as they are not that expensive?? I wanted to be sure before purchasing them.
Thanks
stuart

 

[my67xr]

and a flywheel puller too, check if this one fits, it's what i have for mine
http://www.ebay.com.au/itm/MOTION-P...t=Motors_Automotive_Tools&hash=item20cf134b2b

maybe buy a new loom too, that way if something has been stuffed up or played with you could still have a bike that doesn't start.
ebay has the looms cheap, between $8 and $20

 

[rotn50]

Yes def get a wiring harness also mate, may as well pull the old harness out and just check all the wire terminals are inside the terminal joiners okay and not half out, if its not to much drama you could pull the harness out of the other bike with the different cdi and try that way, thats if the bikes both run a single 5 pin cdi and the other a double 6 pin cdi. These are the same basically but in a different format as i have seen them both setup on 140 lifans, normally the 125 will always run a 5 pin cdi(but have seen the 6pin double plug) and a lifan 140 a 5pin single plug or a 6 pin double plug.

 

[headsmess]

this should be a five minute job.

you say the wirings a confusing mess.

sidecutters. hack the wires from the case, with enough left to play with.

hack the cdi plug off. same deal. leave tails!

right! throw EVERYTHING else away! not the bike! sheeesh...

from the motor, 3 wires go to the cdi! if it has five coming out,the two wires, yellow yellow or yellow white, hack them, (if there). just 12v from generator. pffft. who wants lights?

there should now be, (im sifting through my head, not my stuff!) a blue wire. a red wire. and a black wire. other wires, with PALE greens and purples are shift neutral indicators....guess what? SNIP! following them will show them to come from another place anyway...

black can be green!!!!!

the cdi plug has 5 wires! 3 hook up to the engines 3 wires! one will have a red line somewhere...wire it to red.

solid black is solid green is earth.

one will have a trace of blue possibly. wire it to blue.

thats three wires.

now what?

black white goes to kill switch. leave it floating in the breeze for now.

black yellow goes to coil.


coil may need the other terminal earthed, if its a "twinpin". this will be marked with green, usually.


now that should work....

check plug, check boot, check coil wire, etc.


failure at this point requires new parts. bummer

 

[sdb302]

Hi Guys

I have re-wired the bike with the help from last post.

I fitted the new CDI unit today and after cleaning the carb and crap fuel out of the tank I finally got the bike running!!!

Went on my first ride around the paddock (in 1st gear only!! remember this is my 1st bike!! LOL) I was just starting to think about changing gear to 2nd!! and had a little mis-hap with the bath tub!!!

The result is a cracked casing on the clutch/kick start side which means oil leaking!!DOH!! I managed to strip the cover off and will attempt to get it welded as it looks like Ali, couldn't find and listed on ebay??

Could someone please advise me on what grade of oil I should put in when I re-build it and the amount?
Thanks in advance and to all who have replied.
Stuart

 

[rotn50]

Just a mineral 4 stroke motorcycle oil, Castrol 4t is good. Bout 850mL will be fine, damn dude imagine the carnage when you get it into 4th gear lol

 

[headsmess]

i said FAILURE at this point will require new parts! dangnamit!

SUCCESS shouldnt need em... well,at least busting the case is a result of...um...SUCCESS!

woo hoo! i rule. thangyou, thangyou very much:action-smiley-035:

cases should be a dime a dozen... a few "wanted" posts here should turn a few up locally

where are ya? i got a few depending on engine numbers... oh. wait. 140. no. theyre precious still! hands off! (pitty shops always have some around the back...)

and did i mention i have an AC TIG welder? ali is loverly to weld unless its soaked in oil.

i still reckon its dodgy but as long as its not "structural", try kwiksteel, knead-it, bog... just wash the case really well in petrol til its spotless, then acetone til it seems pointless, then yeah even works on lugs sometimes...sometimes.

oil? anything. absolutely anything. havent tried hypoid dif oil yet, but one day i will! if its slippery, its better than what they put in it over there...

 

[headsmess]

cough cough, ahem.... i see 140.... and case! in the same sentence even!
http://www.miniriders.com/mini-classifieds/38014-akunar-cams-high-comp-pistons-lifan-140cc.html



oh, and first bike. i cant help but think of the start of the "stay upright" course for a bike license.

even if it looks gay as and you feel like a complete nob head... DONT START THE MOTOR!

learn to stop.

repeat the process over and over. roll off throttle, pull clutch, set up front brake (take up the slack), down on the gear lever to first. (a reason why road bikes almost never feature n1234 boxes, in case you gotta dump clutch and get the hell outta there!) then start squeezing the front brakes. the clutch bit seems silly? the motors not running? huh? its about building habits!

get ya mate to push you. remember that you will look gay. you will push him too, right? but get the stopping trick down pat before using the engine. its all about habits. most people dont make it a habit to have to stop suddenly and find out they got it wrong the hard way... panic makes you do strange things, like take baths whilst riding...