Lifan 125cc electrical problem

[Bradsta97]

Hey everyone, I'm new here, my name is Brady, I'm 18 years old and I have a Lifan 125cc pit bike engine 4 gears, electric/kick start. Not too sure on year model.

I have had this problem with my electrical system. The day I had it on my bench trying to start it up with electric start as kick starter has no lever. It kept turning over until it stopped and it blew a fuse

I replaced the fuse but as I plug positive and negative to battery and go ahead and try to start the engine it blow the fuse again

Thinking there must be a short somewhere but I've over looked the wiring harness for bare wires or anything like that but all wires are not damaged.

I left it for the next day. I replaced the fuse again but I took the ground off the engine and lightly tap the engine and it sparks which then causing the fuse to blow.

At the moment I've researched a lot on how to fix it, but to no anvil.

On the side note it has got a new ignition coil, new spark plug, new CDI, new regulator rectifier.

Whether the stator is bad or not I'm not sure

Any advice is good on what's happening to my system

Cheers guys

 

[my67xr]

Welcome to Minirider's,

First up, drop in here and introduce yourself.

Sound like it might be a faulty starter motor to me, or a shorted starter solenoid ?
If the engine has ever been wet it could have rust on the starter motors' armature stack which is rubbing on the magnet's.
It could also have a rusty starter motor/flywheel drive chain and have some seized link's
You can pick up a new starter pretty cheap on ebay, they are easy to change over too.

Cheer's, Craig

 

[Bradsta97]

Thanks Craig, I sure will

Well for start I disconnected from the whole starter motor system and the ground wire still sparks on the engine.

The links are all clean nor are they rusty.

The only time it will create a spark on the engine ground is either when I disconnect the regulator rectifier or stator

I had a mate test my starter solenoid and to him it was all good, no shorts or anything.
I have yet to test my stator as no one in my area knows how to propely test a stator

I've tried testing my stator with a multimeter but not to sure on readings as all readings are different

Anyway cheers

 

[my67xr]

Well you have come to the right place then
Have a read through here-
http://www.miniriders.com/electrica...urce-coil-pulse-coil-regulator-rectifier.html

 

[Bradsta97]

Hey mate thanks by the way, I tested my source coil and pulse/trigger coil

For the source coil, I set it to 2000 ohms and I got 622 ohms out of my source coil and for my pulse/trigger coil, setting it at 200 ohms I got 120.9 ohms

Stator need replacing?

 

[headsmess]

there shouldnt be a fuse between the starter motor and the battery at all?

between the regulator, solenoid, and all low current stuff, sure...but the starter motor can draw a good 50 amps or so. they should be hardwired, with some pretty thick cables, to the battery. solenoid being stuck somewhere in the positive side, of course

test the starter by itself, just apply power from the battery, ignoring solenoids and other stuff. pos to pos and case to negative. at least you can spin it over that way, no probs (if good)

test the solenoid yourself, just wack the two thin wires across a battery, it should click. multimeter across the terminals will go from open circuit to closed circuit.no, it wont fry. the fuse doesnt LIMIT current, it simply burns out if theres something WRONG.

then wire it back up with the starter, same deal... the starter should run only when them two solenoid wires are applied to a battery. (remembering the starter is still hardwired to the battery with its own cables.)

maybe a pic will help clarify... the starter will only RUN when that yellow wire is touched to POSITIVE(+)


(as good as i can draw using GIMP on linux...sorry)

does sound suspiciously like the reccyreg has fried itself though.

 

[Bradsta97]

hey mate thanks for the reply here are some pictures as i wired it up as your picture shown but I've got green and yellow wire and red and yellow wire coming from the starter solenoid and they go into the wiring harness

And I'm trying to add more photos but it isn't working i can only get one up but i don't even know how i did put it up.

 

[headsmess]

doesnt matter what colour they are... just poke on on the neg, and one on the positive, and the starter will go. my pic had no reference to any colour coding conventions.

though an idea to put a multimeter with diode function across them. both ways. it might have a blocking diode in it, be polarity sensitive, and that WILL blow a fuse... so you may only have to swap the wires over.

cut em off short, then whack a spanner across those two big terminals on the solenoid and forget about key start...spanner start its the bushies way of doing it

 

[my67xr]

The source coil is way out of spec, it has too much resistance there.
Replace the stator, you can keep the trigger coil as a spare if you want that is still good.
To swap stator's you'll need a flywheel puller too, like this one-
B 27mm Flywheel Magneto Stator Roller Puller 5cc 14cc PIT Quad Dirt Bike ATV | eBay

With your starter motor solenoid the Yellow w/green stripe goes to earth, and the yellow w/red is the momentary power from the starter button

 

[Bradsta97]

Hey guys, thanks a lot for the feedback, I've managed to get it to start and turn over, the regulator rectifier was fried which was making the ground wire spark, the stator was checked by a friend and is ok and does produce spark, but the problem is now, my new CDI box shows I am getting spark from a little light indicator but I'm getting no spark to my spark plug. The spark plugs coil is brand new but spark plug isn't.

 

[my67xr]

Is the new cdi an performance alloy finned one ?
They aren't that reliable at the best of time's

But i would try a new NGK C7HSA spark plug and see if it spark's then.

Might be worth checking the trigger coil at the rear of the flywheel has minimal clearance too
It just need's to be a business thickness between the pick up coil and the tab on the flywheel

Test out the reading's from the ignition coil too if you can
The reading's are in the testing thread i posted before

 

[Bradsta97]

Cheers mate

Yes the new CDI is one of those performance alloy fined ones, I tried the ordinal one and and had no spark to spark plug

I haven't got a new spark plug yet but I'll let you know when I get one and if it sparks.

With the clearance between the trigger coil and flywheel, I can't get a Business card in there as the coil and stator all go into a single case which gets bolted to the flywheel side

But I do know when it turns over I hear a click when it passes the trigger coil, to me it sound not right, it's giving spark to coil but yea I'm not sure

 

[headsmess]

ewgh, performance CDI...

best performance they provide is fast shipping and headaches galore!


erm, slight possibility that the case isnt earthing properly to the rest of the engine... any paint, gasket goop etc been applied when installing?

worth popping trigger coil off and scraping its mounts slightly. or at least checking for continuity.

the "reverse" type magnetos are usually pretty good on clearance... theres no easy way to adjust them anyways. can try a layer of tape over the magneto "lump", just add another layer each time until it starts to tear because the coil is starting to hit. gives you an idea of the clearance. no more than 1mm!